Planned economy

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Planned_economy 

A planned economy is a type of economic system where the distribution of goods and services or the investment, production and the allocation of capital goods takes place according to economic plans that are either economy-wide or limited to a category of goods and services. A planned economy may use centralized, decentralized, participatory or Soviet-type forms of economic planning. The level of centralization or decentralization in decision-making and participation depends on the specific type of planning mechanism employed.

Socialist states based on the Soviet model have used central planning, although a minority such as the former Socialist Federal Republic of Yugoslavia have adopted some degree of market socialism. Market abolitionist socialism replaces factor markets with direct calculation as the means to coordinate the activities of the various socially owned economic enterprises that make up the economy. More recent approaches to socialist planning and allocation have come from some economists and computer scientists proposing planning mechanisms based on advances in computer science and information technology.

Planned economies contrast with unplanned economies, specifically market economies, where autonomous firms operating in markets make decisions about production, distribution, pricing and investment. Market economies that use indicative planning are variously referred to as planned market economies, mixed economies and mixed market economies. A command economy follows an administrative-command system and uses Soviet-type economic planning which was characteristic of the former Soviet Union and Eastern Bloc before most of these countries converted to market economies. This highlights the central role of hierarchical administration and public ownership of production in guiding the allocation of resources in these economic systems.

Overview

In the Hellenistic and post-Hellenistic world, "compulsory state planning was the most characteristic trade condition for the Egyptian countryside, for Hellenistic India, and to a lesser degree the more barbaric regions of the Seleucid, the Pergamenian, the southern Arabian, and the Parthian empires". Scholars have argued that the Incan economy was a flexible type of command economy, centered around the movement and utilization of labor instead of goods. One view of mercantilism sees it as involving planned economies.

The Soviet-style planned economy in Soviet Russia evolved in the wake of a continuing existing World War I war-economy as well as other policies, known as war communism (1918–1921), shaped to the requirements of the Russian Civil War of 1917–1923. These policies began their formal consolidation under an official organ of government in 1921, when the Soviet government founded Gosplan. However, the period of the New Economic Policy (c. 1921 to c. 1928 intervened before the planned system of regular five-year plans started in 1928.

Nazi Germany's Four Year Plan of 1936 onwards involved elements of state planning in the Reich economy.

After World War II (1939–1945) France and Great Britain practised dirigisme - government direction of the economy through non-coercive means. The Swedish government planned public-housing models in a similar fashion as urban planning in a project called Million Programme, implemented from 1965 to 1974. Some decentralized participation in economic planning occurred across Revolutionary Spain, most notably in Catalonia, during the Spanish Revolution of 1936.

Relationship with socialism

While socialism is not equivalent to economic planning or to the concept of a planned economy, an influential conception of socialism involves the replacement of capital markets with some form of economic planning in order to achieve ex-ante coordination of the economy. The goal of such an economic system would be to achieve conscious control over the economy by the population, specifically so that the use of the surplus product is controlled by the producers. The specific forms of planning proposed for socialism and their feasibility are subjects of the socialist calculation debate.

Computational economic planning

Further information: Government by algorithm

In 1959 Anatoly Kitov proposed a distributed computing system (Project "Red Book", Russian: Красная книга) with a focus on the management of the Soviet economy. Opposition from the Defence Ministry killed Kitov's plan.

In 1971 the socialist Allende administration of Chile launched Project Cybersyn to install a telex machine in every corporation and organisation in the economy for the communication of economic data between firms and the government. The data was also fed into a computer-simulated economy for forecasting. A control room was built for real-time observation and management of the overall economy. The prototype-stage of the project showed promise when it was used to redirect supplies around a trucker's strike, but after CIA-backed Augusto Pinochet led a coup in 1973 that established a military dictatorship under his rule the program was abolished and Pinochet moved Chile towards a more liberalized market economy.

In their book Towards a New Socialism (1993), the computer scientist Paul Cockshott from the University of Glasgow and the economist Allin Cottrell from the Wake Forest University claim to demonstrate how a democratically planned economy built on modern computer technology is possible and drives the thesis that it would be both economically more stable than the free-market economies and also morally desirable.

Cybernetics

The use of computers to coordinate production in an optimal fashion has been variously proposed for socialist economies. The Polish economist Oskar Lange (1904–1965) argued that the computer is more efficient than the market process at solving the multitude of simultaneous equations required for allocating economic inputs efficiently (either in terms of physical quantities or monetary prices).

Salvador Allende's socialist government pioneered the 1970 Chilean distributed decision support system Project Cybersyn in an attempt to move towards a decentralized planned economy with the experimental viable system model of computed organisational structure of autonomous operative units through an algedonic feedback setting and bottom-up participative decision-making in the form of participative democracy by the Cyberfolk component.

Fictional portrayals

The 1888 novel Looking Backward by Edward Bellamy depicts a fictional planned economy in a United States around the year 2000 which has become a socialist utopia.

The World State in Aldous Huxley's Brave New World (1932) and Airstrip One in George Orwell's Nineteen Eighty-Four (1949) provide fictional depictions of command economies, albeit with diametrically opposed aims. The former is a consumer economy designed to engender productivity while the latter is a shortage economy designed as an agent of totalitarian social control. Airstrip One is organized by the euphemistically named Ministry of Plenty.

Other literary portrayals of planned economies include Yevgeny Zamyatin's We (1924), which influenced Orwell's work. Like Nineteen Eighty-Four, Ayn Rand's dystopian 1938 story Anthem offered an artistic portrayal of a command economy that was influenced by We. The difference is that it was a primitivist planned economy as opposed to the advanced technology of We or Brave New World.

Central planning

Advantages

The government can harness land, labor, and capital to serve the economic objectives of the state. Consumer demand can be restrained in favor of greater capital investment for economic development in a desired pattern. In international comparisons, state-socialist nations compared favorably with capitalist nations in health indicators such as infant mortality and life expectancy. However, the reality of this, at least regarding infant mortality, varied depending on whether official Soviet statistics or WHO definitions were used.

The state can begin building massive heavy industries at once in an underdeveloped economy without waiting years for capital to accumulate through the expansion of light industry and without reliance on external financing. This is what happened in the Soviet Union during the 1930s when the government forced the share of gross national income dedicated to private consumption down from 80% to 50%. As a result of this development, the Soviet Union experienced massive growth in heavy industry, with a concurrent massive contraction of its agricultural sector due to the labor shortage.

Disadvantages

Economic instability

Studies of command economies of the Eastern Bloc in the 1950s and 1960s by both American and Eastern European economists found that contrary to the expectations of both groups they showed greater fluctuations in output than market economies during the same period.

Inefficient resource distribution

Critics of planned economies argue that planners cannot detect consumer preferences, shortages and surpluses with sufficient accuracy and therefore cannot efficiently co-ordinate production (in a market economy, a free price system is intended to serve this purpose). This difficulty was notably written about by economists Ludwig von Mises and Friedrich Hayek, who referred to subtly distinct aspects of the problem as the economic calculation problem and local knowledge problem, respectively. These distinct aspects were also present in the economic thought of Michael Polanyi.

Whereas the former stressed the theoretical underpinnings of a market economy to subjective value theory while attacking the labor theory of value, the latter argued that the only way to satisfy individuals who have a constantly changing hierarchy of needs and are the only ones to possess their particular individual's circumstances is by allowing those with the most knowledge of their needs to have it in their power to use their resources in a competing marketplace to meet the needs of the most consumers most efficiently. This phenomenon is recognized as spontaneous order. Additionally, misallocation of resources would naturally ensue by redirecting capital away from individuals with direct knowledge and circumventing it into markets where a coercive monopoly influences behavior, ignoring market signals. According to Tibor Machan, "[w]ithout a market in which allocations can be made in obedience to the law of supply and demand, it is difficult or impossible to funnel resources with respect to actual human preferences and goals".

Suppression of economic democracy and self-management

Economist Robin Hahnel, who supports participatory economics, a form of socialist decentralized planned economy, notes that even if central planning overcame its inherent inhibitions of incentives and innovation, it would nevertheless be unable to maximize economic democracy and self-management, which he believes are concepts that are more intellectually coherent, consistent and just than mainstream notions of economic freedom. Furthermore, Hahnel states:

Combined with a more democratic political system, and redone to closer approximate a best case version, centrally planned economies no doubt would have performed better. But they could never have delivered economic self-management, they would always have been slow to innovate as apathy and frustration took their inevitable toll, and they would always have been susceptible to growing inequities and inefficiencies as the effects of differential economic power grew. Under central planning neither planners, managers, nor workers had incentives to promote the social economic interest. Nor did impeding markets for final goods to the planning system enfranchise consumers in meaningful ways. But central planning would have been incompatible with economic democracy even if it had overcome its information and incentive liabilities. And the truth is that it survived as long as it did only because it was propped up by unprecedented totalitarian political power.

Command economy

Planned economies contrast with command economies in that a planned economy is "an economic system in which the government controls and regulates production, distribution, prices, etc." whereas a command economy necessarily has substantial public ownership of industry while also having this type of regulation. In command economies, important allocation decisions are made by government authorities and are imposed by law.

This is contested by some Marxists. Decentralized planning has been proposed as a basis for socialism and has been variously advocated by anarchists, council communists, libertarian Marxists and other democratic and libertarian socialists who advocate a non-market form of socialism, in total rejection of the type of planning adopted in the economy of the Soviet Union.

Most of a command economy is organized in a top-down administrative model by a central authority, where decisions regarding investment and production output requirements are decided upon at the top in the chain of command, with little input from lower levels. Advocates of economic planning have sometimes been staunch critics of these command economies. Leon Trotsky believed that those at the top of the chain of command, regardless of their intellectual capacity, operated without the input and participation of the millions of people who participate in the economy and who understand/respond to local conditions and changes in the economy. Therefore, they would be unable to effectively coordinate all economic activity.

Historians have associated planned economies with Marxist–Leninist states and the Soviet economic model. Since the 1980s, it has been contested that the Soviet economic model did not actually constitute a planned economy in that a comprehensive and binding plan did not guide production and investment. The further distinction of an administrative-command system emerged as a new designation in some academic circles for the economic system that existed in the former Soviet Union and Eastern Bloc, highlighting the role of centralized hierarchical decision-making in the absence of popular control over the economy. The possibility of a digital planned economy was explored in Chile between 1971 and 1973 with the development of Project Cybersyn and by Aleksandr Aleksandrovich Kharkevich, head of the Department of Technical Physics in Kiev in 1962.

While both economic planning and a planned economy can be either authoritarian or democratic and participatory, democratic socialist critics argue that command economies are necessarily authoritarian or undemocratic in practice. Indicative planning is a form of economic planning in market economies that directs the economy through incentive-based methods. Economic planning can be practiced in a decentralized manner through different government authorities. In some predominantly market-oriented and Western mixed economies, the state utilizes economic planning in strategic industries such as the aerospace industry. Mixed economies usually employ macroeconomic planning while micro-economic affairs are left to the market and price system.

Decentralized planning

A decentralized-planned economy, occasionally called horizontally planned economy due to its horizontalism, is a type of planned economy in which the investment and allocation of consumer and capital goods is explicated accordingly to an economy-wide plan built and operatively coordinated through a distributed network of disparate economic agents or even production units itself. Decentralized planning is usually held in contrast to centralized planning, in particular the Soviet-type economic planning of the Soviet Union's command economy, where economic information is aggregated and used to formulate a plan for production, investment and resource allocation by a single central authority. Decentralized planning can take shape both in the context of a mixed economy as well as in a post-capitalist economic system. This form of economic planning implies some process of democratic and participatory decision-making within the economy and within firms itself in the form of industrial democracy. Computer-based forms of democratic economic planning and coordination between economic enterprises have also been proposed by various computer scientists and radical economists. Proponents present decentralized and participatory economic planning as an alternative to market socialism for a post-capitalist society.

Decentralized planning has been a feature of anarchist and socialist economics. Variations of decentralized planning such as economic democracy, industrial democracy and participatory economics have been promoted by various political groups, most notably anarchists, democratic socialists, guild socialists, libertarian Marxists, libertarian socialists, revolutionary syndicalists and Trotskyists. During the Spanish Revolution, some areas where anarchist and libertarian socialist influence through the CNT and UGT was extensive, particularly rural regions, were run on the basis of decentralized planning resembling the principles laid out by anarcho-syndicalist Diego Abad de Santillan in the book After the Revolution.

Models

Negotiated coordination

Economist Pat Devine has created a model of decentralized economic planning called "negotiated coordination" which is based upon social ownership of the means of production by those affected by the use of the assets involved, with the allocation of consumer and capital goods made through a participatory form of decision-making by those at the most localized level of production. Moreover, organizations that utilize modularity in their production processes may distribute problem solving and decision making.

Participatory planning

See also: Participatory economics

The planning structure of a decentralized planned economy is generally based on a consumers council and producer council (or jointly, a distributive cooperative) which is sometimes called a consumers' cooperative. Producers and consumers, or their representatives, negotiate the quality and quantity of what is to be produced. This structure is central to guild socialism, participatory economics and the economic theories related to anarchism.

Practice

Kerala

Main article: People's Planning in Kerala

See also: District planning in India

Some decentralized participation in economic planning has been implemented in various regions and states in India, most notably in Kerala. Local level planning agencies assess the needs of people who are able to give their direct input through the Gram Sabhas (village-based institutions) and the planners subsequently seek to plan accordingly.

Revolutionary Catalonia

Main article: Collectivist anarchism

See also: Revolutionary Catalonia

Some decentralized participation in economic planning has been implemented across Revolutionary Spain, most notably in Catalonia, during the Spanish Revolution of 1936.

Similar concepts in practice

Community participatory planning

Main article: Participatory planning

The United Nations has developed local projects that promote participatory planning on a community level. Members of communities take decisions regarding community development directly.

Organic compound

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Organic_compound 

 

Methane, CH₄; is among the simplest organic compounds.

In chemistry, many authors consider an organic compound to be any chemical compound that contains carbon-hydrogen or carbon-carbon bonds, although the definition of "organic" versus "inorganic" varies from author to author, and is a topic of debate. For example, methane (CH₄) is considered organic, but whether some other carbon-containing compounds are organic or inorganic varies from author to author, like halides of carbon without carbon-hydrogen bonds (e.g. carbon tetrachloride CCl₄), as well as certain compounds of carbon with nitrogen and oxygen (e.g. cyanide ion CN⁻ and carbonate ion CO2−3, which are generally considered inorganic).

Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise the discipline known as organic chemistry. For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts), along with a few other exceptions (e.g., carbon dioxide, and even hydrogen cyanide despite the fact it contains a carbon-hydrogen bond), are generally not classified as organic compounds and are generally considered inorganic. Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive.

Although organic compounds make up only a small percentage of Earth's crust, they are of central importance because all known life is based on organic compounds. Living things incorporate inorganic carbon compounds into organic compounds through a network of processes (the carbon cycle) that begins with the conversion of carbon dioxide and a hydrogen source like water into simple sugars and other organic molecules by autotrophic organisms using light (photosynthesis) or other sources of energy. Most synthetically-produced organic compounds are ultimately derived from petrochemicals consisting mainly of hydrocarbons, which are themselves formed from the high pressure and temperature degradation of organic matter underground over geological timescales. This ultimate derivation notwithstanding, organic compounds are no longer defined as compounds originating in living things, as they were historically.

In chemical nomenclature, an organyl group, frequently represented by the letter R, refers to any monovalent substituent whose open valence is on a carbon atom.

Definitions of organic vs inorganic

For historical reasons discussed below, a few types of carbon-containing compounds, such as carbides, carbonates (excluding carbonate esters), simple oxides of carbon (for example, CO and CO₂), and cyanides are considered inorganic. Different forms (allotropes) of pure carbon, such as diamond, graphite, fullerenes, and carbon nanotubes are also excluded because they are simple substances composed of only a single element and therefore are not generally considered to be chemical compounds.

It is also important to note that the word "organic" in this context does not mean "natural."

History

Vitalism

Main article: Vitalism

Vitalism was a widespread conception that substances found in organic nature are formed from the chemical elements by the action of a "vital force" or "life-force" (vis vitalis) that only living organisms possess.

In the 1810s, Jöns Jacob Berzelius argued that a regulative force must exist within living bodies. Berzelius also contended that compounds could be distinguished by whether they required any organisms in their synthesis (organic compounds) or whether they did not (inorganic compounds).^[6] Vitalism taught that formation of these "organic" compounds were fundamentally different from the "inorganic" compounds that could be obtained from the elements by chemical manipulations in laboratories.

Vitalism survived for a short period after the formulation of modern ideas about the atomic theory and chemical elements. It first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid, a compound known to occur only in living organisms, from cyanogen. A further experiment was Wöhler's 1828 synthesis of urea from the inorganic salts potassium cyanate and ammonium sulfate. Urea had long been considered an "organic" compound, as it was known to occur only in the urine of living organisms. Wöhler's experiments were followed by many others, in which increasingly complex "organic" substances were produced from "inorganic" ones without the involvement of any living organism, thus disproving vitalism.

Modern classification and ambiguities

The L-isoleucine molecule, C₆H₁₃NO₂, showing features typical of organic compounds. Carbon atoms are in black, hydrogens gray, oxygens red, and nitrogen blue.

Although vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds. The modern meaning of organic compound is any compound that contains a significant amount of carbon—even though many of the organic compounds known today have no connection to any substance found in living organisms. The term carbogenic has been proposed by E. J. Corey as a modern alternative to organic, but this neologism remains relatively obscure.

The organic compound L-isoleucine molecule presents some features typical of organic compounds: carbon–carbon bonds, carbon–hydrogen bonds, as well as covalent bonds from carbon to oxygen and to nitrogen.

As described in detail below, any definition of organic compound that uses simple, broadly-applicable criteria turns out to be unsatisfactory, to varying degrees. The modern, commonly accepted definition of organic compound essentially amounts to any carbon-containing compound, excluding several classes of substances traditionally considered 'inorganic'. However, the list of substances so excluded varies from author to author. Still, it is generally agreed upon that there are (at least) a few carbon-containing compounds that should not be considered organic. For instance, almost all authorities would require the exclusion of alloys that contain carbon, including steel (which contains cementite, Fe₃C), as well as other metal and semimetal carbides (including "ionic" carbides, e.g, Al₄C₃ and CaC₂ and "covalent" carbides, e.g. B₄C and SiC, and graphite intercalation compounds, e.g. KC₈). Other compounds and materials that are considered 'inorganic' by most authorities include: metal carbonates, simple oxides (CO, CO₂, and arguably, C₃O₂), the allotropes of carbon, cyanide derivatives not containing an organic residue (e.g., KCN, (CN)₂, BrCN, CNO⁻, etc.), and heavier analogs thereof (e.g., CP⁻ 'cyaphide anion', CSe₂, COS; although CS₂ 'carbon disulfide' is often classed as an organic solvent). Halides of carbon without hydrogen (e.g., CF₄ and CClF₃), phosgene (COCl₂), carboranes, metal carbonyls (e.g., nickel carbonyl), mellitic anhydride (C₁₂O₉), and other exotic oxocarbons are also considered inorganic by some authorities.

Nickel carbonyl (Ni(CO)₄) and other metal carbonyls are often volatile liquids, like many organic compounds, yet they contain only carbon bonded to a transition metal and to oxygen, and are often prepared directly from metal and carbon monoxide. Nickel carbonyl is typically classified as an organometallic compound as it satisfies the broad definition that organometallic chemistry covers all compounds that contain at least one carbon to metal covalent bond; it is debatable whether organometallic compounds form a subset of organic compounds, however. For example, the evidence of covalent Fe-C bonding in cementite, a major component of steel, places it within this broad definition of organometallic, yet steel and other carbon-containing alloys are seldom regarded as organic compounds. Thus, it is unclear whether the definition of organometallic should be narrowed, whether these considerations imply that organometallic compounds are not necessarily organic, or both.

Metal complexes with organic ligands but no carbon-metal bonds (e.g., Cu(OAc)₂) are not considered organometallic; instead, they are classed as metalorganic. Likewise, it is also unclear whether metalorganic compounds should automatically be considered organic.

The relatively narrow definition of organic compounds as those containing C-H bonds excludes compounds that are (historically and practically) considered organic. Neither urea nor oxalic acid are organic by this definition, yet they were two key compounds in the vitalism debate. The IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid. Other compounds lacking C-H bonds but traditionally considered organic include benzenehexol, mesoxalic acid, and carbon tetrachloride. Mellitic acid, which contains no C-H bonds, is considered a possible organic substance in Martian soil. Terrestrially, it, and its anhydride, mellitic anhydride, are associated with the mineral mellite (Al₂C₆(COO)₆·16H₂O).

A slightly broader definition of the organic compound includes all compounds bearing C-H or C-C bonds. This would still exclude urea. Moreover, this definition still leads to somewhat arbitrary divisions in sets of carbon-halogen compounds. For example, CF₄ and CCl₄ would be considered by this rule to be "inorganic", whereas CF₃H, CHCl₃, and C₂Cl₆ would be organic, though these compounds share many physical and chemical properties.

Classification

Main article: Organic chemistry §  compounds

Organic compounds may be classified in a variety of ways. One major distinction is between natural and synthetic compounds. Organic compounds can also be classified or subdivided by the presence of heteroatoms, e.g., organometallic compounds, which feature bonds between carbon and a metal, and organophosphorus compounds, which feature bonds between carbon and a phosphorus.

Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers.

Natural compounds

Natural compounds refer to those that are produced by plants or animals. Many of these are still extracted from natural sources because they would be more expensive to produce artificially. Examples include most sugars, some alkaloids and terpenoids, certain nutrients such as vitamin B₁₂, and, in general, those natural products with large or stereoisometrically complicated molecules present in reasonable concentrations in living organisms.

Further compounds of prime importance in biochemistry are antigens, carbohydrates, enzymes, hormones, lipids and fatty acids, neurotransmitters, nucleic acids, proteins, peptides and amino acids, lectins, vitamins, and fats and oils.

Synthetic compounds

Compounds that are prepared by reaction of other compounds are known as "synthetic". They may be either compounds that are already found in plants/animals or those artificial compounds that do not occur naturally.

Most polymers (a category that includes all plastics and rubbers) are organic synthetic or semi-synthetic compounds.

Biotechnology

Many organic compounds—two examples are ethanol and insulin—are manufactured industrially using organisms such as bacteria and yeast. Typically, the DNA of an organism is altered to express compounds not ordinarily produced by the organism. Many such biotechnology-engineered compounds did not previously exist in nature.

Databases

• The CAS database is the most comprehensive repository for data on organic compounds. The search tool SciFinder is offered.
• The Beilstein database contains information on 9.8 million substances, covers the scientific literature from 1771 to the present, and is today accessible via Reaxys. Structures and a large diversity of physical and chemical properties are available for each substance, with reference to original literature.
• PubChem contains 18.4 million entries on compounds and especially covers the field of medicinal chemistry.

A great number of more specialized databases exist for diverse branches of organic chemistry.

Structure determination

Main article: Structure determination

The main tools are proton and carbon-13 NMR spectroscopy, IR Spectroscopy, Mass spectrometry, UV/Vis Spectroscopy and X-ray crystallography.

Total synthesis

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Total_synthesis 

Total synthesis is the complete chemical synthesis of a complex molecule, often a natural product, from simple, commercially-available precursors. It usually refers to a process not involving the aid of biological processes, which distinguishes it from semisynthesis. Syntheses may sometimes conclude at a precursor with further known synthetic pathways to a target molecule, in which case it is known as a formal synthesis. Total synthesis target molecules can be natural products, medicinally-important active ingredients, known intermediates, or molecules of theoretical interest. Total synthesis targets can also be organometallic or inorganic, though these are rarely encountered. Total synthesis projects often require a wide diversity of reactions and reagents, and subsequently requires broad chemical knowledge and training to be successful.

Often, the aim is to discover a new route of synthesis for a target molecule for which there already exist known routes. Sometimes, however, no route exists, and chemists wish to find a viable route for the first time. Total synthesis is particularly important for the discovery of new chemical reactions and new chemical reagents, as well as establishing synthetic routes for medicinally important compounds.

Scope and definitions

There are numerous classes of natural products for which total synthesis is applied to. These include (but are not limited to): terpenes, alkaloids, polyketides and polyethers. Total synthesis targets are sometimes referred to by their organismal origin such as plant, marine, and fungal. The term total synthesis is less frequently but still accurately applied to the synthesis of natural polypeptides and polynucleotides. The peptide hormones oxytocin and vasopressin were isolated and their total syntheses first reported in 1954. It is not uncommon for natural product targets to feature multiple structural components of several natural product classes.

Aims

Although untrue from a historical perspective (see the history of the steroid, cortisone), total synthesis in the modern age has largely been an academic endeavor (in terms of manpower applied to problems). Industrial chemical needs often differ from academic focuses. Typically, commercial entities may pick up particular avenues of total synthesis efforts and expend considerable resources on particular natural product targets, especially if semi-synthesis can be applied to complex, natural product-derived drugs. Even so, for decades there has been a continuing discussion regarding the value of total synthesis as an academic enterprise. While there are some outliers, the general opinions are that total synthesis has changed in recent decades, will continue to change, and will remain an integral part of chemical research. Within these changes, there has been increasing focus on improving the practicality and marketability of total synthesis methods. The Phil S. Baran group at Scripps, a notable pioneer of practical synthesis have endeavored to create scalable and high efficiency syntheses that would have more immediate uses outside of academia.

History

Vitamin B₁₂ total synthesis: Retrosynthetic analysis of the Woodward–Eschenmoser total synthesis that was reported in two variants by these groups in 1972. The work involved more than 100 PhD trainees and postdoctoral fellows from 19 different countries. The retrosynthesis presents the disassembly of the target vitamin in a manner that makes chemical sense for its eventual forward construction. The target, Vitamin B₁₂ (I), is envisioned being prepared by the simple addition of its tail, which had earlier been shown to be feasible. The needed precursor, cobyric acid (II), then becomes the target and constitutes the "corrin core" of the vitamin, and its preparation was envisaged to be possible via two pieces, a "western" part composed of the A and D rings (III) and an "eastern" part composed of the B and C rings (IV). The restrosynthetic analysis then envisions the starting materials required to make these two complex parts, the yet complex molecules V–VIII.

Friedrich Wöhler discovered that an organic substance, urea, could be produced from inorganic starting materials in 1828. That was an important conceptual milestone in chemistry by being the first example of a synthesis of a substance that had been known only as a byproduct of living processes. Wöhler obtained urea by treating silver cyanate with ammonium chloride, a simple, one-step synthesis:

AgNCO + NH₄Cl → (NH₂)₂CO + AgCl

Camphor was a scarce and expensive natural product with a worldwide demand. Haller and Blanc synthesized it from camphor acid; however, the precursor, camphoric acid, had an unknown structure. When Finnish chemist Gustav Komppa synthesized camphoric acid from diethyl oxalate and 3,3-dimethylpentanoic acid in 1904, the structure of the precursors allowed contemporary chemists to infer the complicated ring structure of camphor. Shortly thereafter, William Perkin published another synthesis of camphor. The work on the total chemical synthesis of camphor allowed Komppa to begin industrial production of the compound, in Tainionkoski, Finland, in 1907.

The American chemist Robert Burns Woodward was a pre-eminent figure in developing total syntheses of complex organic molecules, some of his targets being cholesterol, cortisone, strychnine, lysergic acid, reserpine, chlorophyll, colchicine, vitamin B₁₂, and prostaglandin F-2a.

Vincent du Vigneaud was awarded the 1955 Nobel Prize in Chemistry for the total synthesis of the natural polypeptide oxytocin and vasopressin, which reported in 1954 with the citation "for his work on biochemically important sulphur compounds, especially for the first synthesis of a polypeptide hormone."

Another gifted chemist is Elias James Corey, who won the Nobel Prize in Chemistry in 1990 for lifetime achievement in total synthesis and for the development of retrosynthetic analysis.

List of notable total syntheses

• Quinine total synthesis
• Vitamin B₁₂ total synthesis
• Strychnine total synthesis
• Paclitaxel (Taxol) total synthesis

Industrial applications of nanotechnology

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Industrial_applications_of_nanotechnology

Nanotechnology is impacting the field of consumer goods, several products that incorporate nanomaterials are already in a variety of items; many of which people do not even realize contain nanoparticles, products with novel functions ranging from easy-to-clean to scratch-resistant. Examples of that car bumpers are made lighter, clothing is more stain repellant, sunscreen is more radiation resistant, synthetic bones are stronger, cell phone screens are lighter weight, glass packaging for drinks leads to a longer shelf-life, and balls for various sports are made more durable. Using nanotech, in the mid-term modern textiles will become "smart", through embedded "wearable electronics", such novel products have also a promising potential especially in the field of cosmetics, and has numerous potential applications in heavy industry. Nanotechnology is predicted to be a main driver of technology and business in this century and holds the promise of higher performance materials, intelligent systems and new production methods with significant impact for all aspects of society.

Foods

A complex set of engineering and scientific challenges in the food and bioprocessing industry for manufacturing high quality and safe food through efficient and sustainable means can be solved through nanotechnology. Bacteria identification and food quality monitoring using biosensors; intelligent, active, and smart food packaging systems; nanoencapsulation of bioactive food compounds are few examples of emerging applications of nanotechnology for the food industry. Nanotechnology can be applied in the production, processing, safety and packaging of food. A nanocomposite coating process could improve food packaging by placing anti-microbial agents directly on the surface of the coated film. Nanocomposites could increase or decrease gas permeability of different fillers as is needed for different products. They can also improve the mechanical and heat-resistance properties and lower the oxygen transmission rate. Research is being performed to apply nanotechnology to the detection of chemical and biological substances for sensanges in foods.

A complex set of engineering and scientific challenges in the food and bioprocessing industry for manufacturing high quality and safe food through efficient and sustainable means can be solved through nanotechnology. Bacteria identification and food quality monitoring using biosensors; intelligent, active, and smart food packaging systems; nanoencapsulation of bioactive food compounds are few examples of emerging applications of nanotechnology for the food industry. Nanotechnology can be applied in the production, processing, safety and packaging of food. A nanocomposite coating process could improve food packaging by placing anti-microbial agents directly on the surface of the coated film. Nanocomposites could increase or decrease gas permeability of different fillers as is needed for different products. They can also improve the mechanical and heat-resistance properties and lower the oxygen transmission rate. Research is being performed to apply nanotechnology to the detection of chemical and biological substances for sensanges in foods.

Nano-foods

New foods are among the nanotechnology-created consumer products coming onto the market at the rate of 3 to 4 per week, according to the Project on Emerging Nanotechnologies (PEN), based on an inventory it has drawn up of 609 known or claimed nano-products. On PEN's list are three foods—a brand of canola cooking oil called Canola Active Oil, a tea called Nanotea and a chocolate diet shake called Nanoceuticals Slim Shake Chocolate. According to company information posted on PEN's Web site, the canola oil, by Shemen Industries of Israel, contains an additive called "nanodrops" designed to carry vitamins, minerals and phytochemicals through the digestive system and urea. The shake, according to U.S. manufacturer RBC Life Sciences Inc., uses cocoa infused "NanoClusters" to enhance the taste and health benefits of cocoa without the need for extra sugar.

Consumer goods

Surfaces and coatings

The most prominent application of nanotechnology in the household is self-cleaning or "easy-to-clean" surfaces on ceramics or glasses. Nanoceramic particles have improved the smoothness and heat resistance of common household equipment such as the flat iron.

The first sunglasses using protective and anti-reflective ultrathin polymer coatings are on the market. For optics, nanotechnology also offers scratch resistant surface coatings based on nanocomposites. Nano-optics could allow for an increase in precision of pupil repair and other types of laser eye surgery.

Textiles

The use of engineered nanofibers already makes clothes water- and stain-repellent or wrinkle-free. Textiles with a nanotechnological  can be washed less frequently and at lower temperatures. Nanotechnology has been used to integrate tiny carbon particles membrane and guarantee full-surface protection from electrostatic charges for the wearer. Many other applications have been developed by research institutions such as the Textiles Nanotechnology Laboratory at Cornell University, and the UK's Dstl and its spin out company P2i.

Sports

Nanotechnology may also play a role in sports such as soccer, football, and baseball. Materials for new athletic shoes may be made in order to make the shoe lighter (and the athlete faster). Baseball bats already on the market are made with carbon nanotubes that reinforce the resin, which is said to improve its performance by making it lighter. Other items such as sport towels, yoga mats, exercise mats are on the market and used by players in the National Football League, which use antimicrobial nanotechnology to prevent parasuram from illnesses caused by bacteria such as Methicillin-resistant Staphylococcus aureus (commonly known as MRSA).

Aerospace and vehicle manufacturers

Lighter and stronger materials will be of immense use to aircraft manufacturers, leading to increased performance. Spacecraft will also benefit, where weight is a major factor. Nanotechnology might thus help to reduce the size of equipment and thereby decrease fuel-consumption required to get it airborne. Hang gliders may be able to halve their weight while increasing their strength and toughness through the use of nanotech materials. Nanotech is lowering the mass of supercapacitors that will increasingly be used to give power to assistive electrical motors for launching hang gliders off flatland to thermal-chasing altitudes.

Much like aerospace, lighter and stronger materials would be useful for creating vehicles that are both faster and safer. Combustion engines might also benefit from parts that are more hard-wearing and more heat-resistant.

Military

Biological sensors

Nanotechnology can improve the military’s ability to detect biological agents. By using nanotechnology, the military would be able to create sensor systems that could detect biological agents. The sensor systems are already well developed and will be one of the first forms of nanotechnology that the military will start to use.

Uniform material

Nanoparticles can be injected into the material on soldiers’ uniforms to not only make the material more durable, but also to protect soldiers from many different dangers such as high temperatures, impacts and chemicals. The nanoparticles in the material protect soldiers from these dangers by grouping together when something strikes the armor and stiffening the area of impact. This stiffness helps lessen the impact of whatever hit the armor, whether it was extreme heat or a blunt force. By reducing the force of the impact, the nanoparticles protect the soldier wearing the uniform from any injury the impact could have caused.

Another way nanotechnology can improve soldiers’ uniforms is by creating a better form of camouflage. Mobile pigment nanoparticles injected into the material can produce a better form of camouflage. These mobile pigment particles would be able to change the color of the uniforms depending upon the area that the soldiers are in. There is still much research being done on this self-changing camouflage.

Nanotechnology can improve thermal camouflage. Thermal camouflage helps protect soldiers from people who are using night vision technology. Surfaces of many different military items can be designed in a way that electromagnetic radiation can help lower the infrared signatures of the object that the surface is on. Surfaces of soldiers’ uniforms and surfaces of military vehicle are a few surfaces that can be designed in this way. By lowering the infrared signature of both the soldiers and the military vehicles the soldiers are using, it will provide better protection from infrared guided weapons or infrared surveillance sensors.

Communication method

There is a way to use nanoparticles to create coated polymer threads that can be woven into soldiers’ uniforms. These polymer threads could be used as a form of communication between the soldiers. The system of threads in the uniforms could be set to different light wavelengths, eliminating the ability for anyone else to listen in. This would lower the risk of having anything intercepted by unwanted listeners.

Medical system

A medical surveillance system for soldiers to wear can be made using nanotechnology. This system would be able to watch over their health and stress levels. The systems would be able to react to medical situations by releasing drugs or compressing wounds as necessary. This means that if the system detected an injury that was bleeding, it would be able to compress around the wound until further medical treatment could be received. The system would also be able to release drugs into the soldier’s body for health reasons, such as pain killers for an injury. The system would be able to inform the medics at base of the soldier’s health status at all times that the soldier is wearing the system. The energy needed to communicate this information back to base would be produced through the soldier’s body movements.

Weapons

Nanoweapon is the name given to military technology currently under development which seeks to exploit the power of nanotechnology in the modern battlefield.

Risks in military

• People such as state agencies, criminals and enterprises could use nano-robots to eavesdrop on conversations held in private.
• Grey goo: an uncontrollable, self-replicating nano-machine or robot.
• Nanoparticles used in different military materials could potentially be a hazard to the soldiers that are wearing the material, if the material is allowed to get worn out. As the uniforms wear down it is possible for nanomaterial to break off and enter the soldiers’ bodies. Having nanoparticles entering the soldiers’ bodies would be very unhealthy and could seriously harm them. There is not a lot of information on what the actual damage to the soldiers would be, but there have been studies on the effect of nanoparticles entering a fish through its skin. The studies showed that the different fish in the study suffered from varying degrees of brain damage. Although brain damage would be a serious negative effect, the studies also say that the results cannot be taken as an accurate example of what would happen to soldiers if nanoparticles entered their bodies. There are very strict regulations on the scientists that manufacture products with nanoparticles. With these strict regulations, they are able to largely decrease the danger of nanoparticles wearing off of materials and entering the soldiers’ systems.

Catalysis

Chemical catalysis benefits especially from nanoparticles, due to the extremely large surface-to-volume ratio. The application potential of nanoparticles in catalysis ranges from fuel cell to catalytic converters and photocatalytic devices. Catalysis is also important for the production of chemicals. For example, nanoparticles with a distinct chemical surrounding (ligands), or specific optical properties.

Platinum nanoparticles are being considered in the next generation of automotive catalytic converters because the very high surface area of nanoparticles could reduce the amount of platinum required. However, some concerns have been raised due to experiments demonstrating that they will spontaneously combust if methane is mixed with the ambient air. Ongoing research at the Centre National de la Recherche Scientifique (CNRS) in France may resolve their true usefulness for catalytic applications. Nanofiltration may come to be an important application, although future research must be careful to investigate possible toxicity.

Construction

Nanotechnology has the potential to make construction faster, cheaper, safer, and more varied. Automation of nanotechnology construction can allow for the creation of structures from advanced homes to massive skyscrapers much more quickly and at much lower cost. In the near future, Nanotechnology can be used to sense cracks in foundations of architecture and can send nanobots to repair them.

Nanotechnology is an active research area that encompasses a number of disciplines such as electronics, bio-mechanics and coatings. These disciplines assist in the areas of civil engineering and construction materials. If nanotechnology is implemented in the construction of homes and infrastructure, such structures will be stronger. If buildings are stronger, then fewer of them will require reconstruction and less waste will be produced.

Nanotechnology in construction involves using nanoparticles such as alumina and silica. Manufacturers are also investigating the methods of producing nano-cement. If cement with nano-size particles can be manufactured and processed, it will open up a large number of opportunities in the fields of ceramics, high strength composites and electronic applications. 

Nanomaterials still have a high cost relative to conventional materials, meaning that they are not likely to feature in high-volume building materials. The day when this technology slashes the consumption of structural steel has not yet been contemplated.

Cement

Much analysis of concrete is being done at the nano-level in order to understand its structure. Such analysis uses various techniques developed for study at that scale such as Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Focused Ion Beam (FIB). This has come about as a side benefit of the development of these instruments to study the nanoscale in general, but the understanding of the structure and behavior of concrete at the fundamental level is an important and very appropriate use of nanotechnology. One of the fundamental aspects of nanotechnology is its interdisciplinary nature and there has already been cross over research between the mechanical modeling of bones for medical engineering to that of concrete which has enabled the study of chloride diffusion in concrete (which causes corrosion of reinforcement). Concrete is, after all, a macro-material strongly influenced by its nano-properties and understanding it at this new level is yielding new avenues for improvement of strength, durability and monitoring as outlined in the following paragraphs

Silica (SiO2) is present in conventional concrete as part of the normal mix. However, one of the advancements made by the study of concrete at the nanoscale is that particle packing in concrete can be improved by using nano-silica which leads to a densifying of the micro and nanostructure resulting in improved mechanical properties. Nano-silica addition to cement based materials can also control the degradation of the fundamental C-S-H (calcium-silicatehydrate) reaction of concrete caused by calcium leaching in water as well as block water penetration and therefore lead to improvements in durability. Related to improved particle packing, high energy milling of ordinary Portland cement (OPC) clinker and standard sand, produces a greater particle size diminution with respect to conventional OPC and, as a result, the compressive strength of the refined material is also 3 to 6 times higher (at different ages).

Steel

Steel is a widely available material that has a major role in the construction industry. The use of nanotechnology in steel helps to improve the physical properties of steel. Fatigue, or the structural failure of steel, is due to cyclic loading. Current steel designs are based on the reduction in the allowable stress, service life or regular inspection regime. This has a significant impact on the life-cycle costs of structures and limits the effective use of resources. Stress risers are responsible for initiating cracks from which fatigue failure results. The addition of copper nanoparticles reduces the surface un-evenness of steel, which then limits the number of stress risers and hence fatigue cracking. Advancements in this technology through the use of nanoparticles would lead to increased safety, less need for regular inspection, and more efficient materials free from fatigue issues for construction.

Steel cables can be strengthened using carbon nanotubes. Stronger cables reduce the costs and period of construction, especially in suspension bridges, as the cables are run from end to end of the span.

The use of vanadium and molybdenum nanoparticles improves the delayed fracture problems associated with high strength bolts. This reduces the effects of hydrogen embrittlement and improves steel micro-structure by reducing the effects of the inter-granular cementite phase.

Welds and the Heat Affected Zone (HAZ) adjacent to welds can be brittle and fail without warning when subjected to sudden dynamic loading. The addition of nanoparticles such as magnesium and calcium makes the HAZ grains finer in plate steel. This nanoparticle addition leads to an increase in weld strength. The increase in strength results in a smaller resource requirement because less material is required in order to keep stresses within allowable limits.

Wood

Nanotechnology represents a major opportunity for the wood industry to develop new products, substantially reduce processing costs, and open new markets for biobased materials.

Wood is also composed of nanotubes or “nanofibrils”; namely, lignocellulosic (woody tissue) elements which are twice as strong as steel. Harvesting these nanofibrils would lead to a new paradigm in sustainable construction as both the production and use would be part of a renewable cycle. Some developers have speculated that building functionality onto lignocellulosic surfaces at the nanoscale could open new opportunities for such things as self-sterilizing surfaces, internal self-repair, and electronic lignocellulosic devices. These non-obtrusive active or passive nanoscale sensors would provide feedback on product performance and environmental conditions during service by monitoring structural loads, temperatures, moisture content, decay fungi, heat losses or gains, and loss of conditioned air. Currently, however, research in these areas appears limited.

Due to its natural origins, wood is leading the way in cross-disciplinary research and modelling techniques. BASF have developed a highly water repellent coating based on the actions of the lotus leaf as a result of the incorporation of silica and alumina nanoparticles and hydrophobic polymers. Mechanical studies of bones have been adapted to model wood, for instance in the drying process.

Glass

Research is being carried out on the application of nanotechnology to glass, another important material in construction. Titanium dioxide (TiO₂) nanoparticles are used to coat glazing since it has sterilizing and anti-fouling properties. The particles catalyze powerful reactions that break down organic pollutants, volatile organic compounds and bacterial membranes. TiO₂ is hydrophilic (attraction to water), which can attract rain drops that then wash off the dirt particles. Thus the introduction of nanotechnology in the Glass industry, incorporates the self-cleaning property of glass.

Fire-protective glass is another application of nanotechnology. This is achieved by using a clear intumescent layer sandwiched between glass panels (an interlayer) formed of silica nanoparticles (SiO₂), which turns into a rigid and opaque fire shield when heated. Most of glass in construction is on the exterior surface of buildings. So the light and heat entering the building through glass has to be prevented. The nanotechnology can provide a better solution to block light and heat coming through windows.

Coatings

Coatings is an important area in construction coatings are extensively use to paint the walls, doors, and windows. Coatings should provide a protective layer bound to the base material to produce a surface of the desired protective or functional properties. The coatings should have self healing capabilities through a process of "self-assembly". Nanotechnology is being applied to paints to obtained the coatings having self healing capabilities and corrosion protection under insulation. Since these coatings are hydrophobic and repels water from the metal pipe and can also protect metal from salt water attack.

Nanoparticle based systems can provide better adhesion and transparency. The TiO₂ coating captures and breaks down organic and inorganic air pollutants by a photocatalytic process, which leads to putting roads to good environmental use.

Fire Protection and detection

Fire resistance of steel structures is often provided by a coating produced by a spray-on-cementitious process. The nano-cement has the potential to create a new paradigm in this area of application because the resulting material can be used as a tough, durable, high temperature coating. It provides a good method of increasing fire resistance and this is a cheaper option than conventional insulation.

Risks in construction

In building construction nanomaterials are widely used from self-cleaning windows to flexible solar panels to wi-fi blocking paint. The self-healing concrete, materials to block ultraviolet and infrared radiation, smog-eating coatings and light-emitting walls and ceilings are the new nanomaterials in construction. Nanotechnology is a promise for making the "smart home" a reality. Nanotech-enabled sensors can monitor temperature, humidity, and airborne toxins, which needs nanotech-based improved batteries. The building components will be intelligent and interactive since the sensor uses wireless components, it can collect the wide range of data.

If nanosensors and nanomaterials become an everyday part of the buildings, as with smart homes, what are the consequences of these materials on human beings?

1. Effect of nanoparticles on health and environment: Nanoparticles may also enter the body if building water supplies are filtered through commercially available nanofilters. Airborne and waterborne nanoparticles enter from building ventilation and wastewater systems.
2. Effect of nanoparticles on societal issues: As sensors become commonplace, a loss of privacy and autonomy may result from users interacting with increasingly intelligent building components.