Chemistry is the scientific discipline involved with elements and compounds composed of atoms and ions: their composition, properties and the changes they undergo during a reaction with other substances. In the scope of its subject, chemistry occupies an intermediate position between physics and biology, it is sometimes called the central science because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant chemistry, the formation of igneous rocks, how atmospheric ozone is formed and how environmental pollutants are degraded, the properties of the soil on the moon, how medications work, how to collect DNA evidence at a crime scene. Chemistry addresses topics such as how atoms and molecules interact via chemical bonds to form new chemical compounds. There are four types of chemical bonds: covalent bonds, in which compounds share one or more electron; the word chemistry comes from alchemy, which referred to an earlier set of practices that encompassed elements of chemistry, philosophy, astronomy and medicine.
It is seen as linked to the quest to turn lead or another common starting material into gold, though in ancient times the study encompassed many of the questions of modern chemistry being defined as the study of the composition of waters, growth, disembodying, drawing the spirits from bodies and bonding the spirits within bodies by the early 4th century Greek-Egyptian alchemist Zosimos. An alchemist was called a'chemist' in popular speech, the suffix "-ry" was added to this to describe the art of the chemist as "chemistry"; the modern word alchemy in turn is derived from the Arabic word al-kīmīā. In origin, the term is borrowed from the Greek χημία or χημεία; this may have Egyptian origins since al-kīmīā is derived from the Greek χημία, in turn derived from the word Kemet, the ancient name of Egypt in the Egyptian language. Alternately, al-kīmīā may derive from χημεία, meaning "cast together"; the current model of atomic structure is the quantum mechanical model. Traditional chemistry starts with the study of elementary particles, molecules, metals and other aggregates of matter.
This matter can be studied in isolation or in combination. The interactions and transformations that are studied in chemistry are the result of interactions between atoms, leading to rearrangements of the chemical bonds which hold atoms together; such behaviors are studied in a chemistry laboratory. The chemistry laboratory stereotypically uses various forms of laboratory glassware; however glassware is not central to chemistry, a great deal of experimental chemistry is done without it. A chemical reaction is a transformation of some substances into one or more different substances; the basis of such a chemical transformation is the rearrangement of electrons in the chemical bonds between atoms. It can be symbolically depicted through a chemical equation, which involves atoms as subjects; the number of atoms on the left and the right in the equation for a chemical transformation is equal. The type of chemical reactions a substance may undergo and the energy changes that may accompany it are constrained by certain basic rules, known as chemical laws.
Energy and entropy considerations are invariably important in all chemical studies. Chemical substances are classified in terms of their structure, phase, as well as their chemical compositions, they can be analyzed using the tools of e.g. spectroscopy and chromatography. Scientists engaged in chemical research are known as chemists. Most chemists specialize in one or more sub-disciplines. Several concepts are essential for the study of chemistry; the particles that make up matter have rest mass as well – not all particles have rest mass, such as the photon. Matter can be a mixture of substances; the atom is the basic unit of chemistry. It consists of a dense core called the atomic nucleus surrounded by a space occupied by an electron cloud; the nucleus is made up of positively charged protons and uncharged neutrons, while the electron cloud consists of negatively charged electrons which orbit the nucleus. In a neutral atom, the negatively charged electrons balance out the positive charge of the protons.
The nucleus is dense. The atom is the smallest entity that can be envisaged to retain the chemical properties of the element, such as electronegativity, ionization potential, preferred oxidation state, coordination number, preferred types of bonds to form. A chemical element is a pure substance, composed of a single type of atom, characterized by its particular number of protons in the nuclei of its atoms, known as the atomic number and represented by the symbol Z; the mass number is the sum of the number of neutrons in a nucleus. Although all the nuclei of all atoms belonging to one element will have the same
Chemical & Engineering News
Chemical & Engineering News is a weekly trade magazine published by the American Chemical Society, providing professional and technical information in the fields of chemistry and chemical engineering. It includes information on recent news and research in these fields and employment information and industry news and policy news, funding in these fields, special reports; the magazine is available to all members of the American Chemical Society. In addition, the front part of the magazine is available online for free for anyone to view, but a subscription is required to see further content; the magazine was established in 1923, has been on the internet since 1998. The editor-in-chief is Bibiana Campos Seijo; the magazine is abstracted and indexed in Chemical Abstracts Service, Science Citation Index, Scopus. Official website
Phenylalanine is an essential α-amino acid with the formula C9H11NO2. It can be viewed as a benzyl group substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of alanine; this essential amino acid is classified as neutral, nonpolar because of the inert and hydrophobic nature of the benzyl side chain. The L-isomer is used to biochemically form proteins, coded for by DNA. Phenylalanine is a precursor for tyrosine, the monoamine neurotransmitters dopamine and epinephrine, the skin pigment melanin, it is encoded by the codons UUU and UUC. Phenylalanine is found in the breast milk of mammals, it is used in the manufacture of food and drink products and sold as a nutritional supplement for its reputed analgesic and antidepressant effects. It is a direct precursor to the neuromodulator phenethylamine, a used dietary supplement; as an essential amino acid, phenylalanine is not synthesized de novo in humans and other animals, who must ingest phenylalanine or phenylalanine-containing proteins.
The first description of phenylalanine was made in 1879, when Schulze and Barbieri identified a compound with the empirical formula, C9H11NO2, in yellow lupine seedlings. In 1882, Erlenmeyer and Lipp first synthesized phenylalanine from phenylacetaldehyde, hydrogen cyanide, ammonia; the genetic codon for phenylalanine was first discovered by J. Heinrich Matthaei and Marshall W. Nirenberg in 1961, they showed that by using mRNA to insert multiple uracil repeats into the genome of the bacterium E. coli, they could cause the bacterium to produce a polypeptide consisting of repeated phenylalanine amino acids. This discovery helped to establish the nature of the coding relationship that links information stored in genomic nucleic acid with protein expression in the living cell. Good sources of phenylalanine are eggs, liver, beef and soybeans; the Food and Nutrition Board of the U. S. Institute of Medicine set Recommended Dietary Allowances for essential amino acids in 2002. For phenylalanine plus tyrosine, for adults 19 years and older, 33 mg/kg body weight/day.
L-Phenylalanine is biologically converted into L-tyrosine, another one of the DNA-encoded amino acids. L-tyrosine in turn is converted into L-DOPA, further converted into dopamine and epinephrine; the latter three are known as the catecholamines. Phenylalanine uses the same active transport channel as tryptophan to cross the blood–brain barrier. In excessive quantities, supplementation can interfere with the production of serotonin and other aromatic amino acids as well as nitric oxide due to the overuse of the associated cofactors, iron or tetrahydrobiopterin; the corresponding enzymes in for those compounds are the aromatic amino acid hydroxylase family and nitric oxide synthase. Phenylalanine is the starting compound used in the synthesis of flavonoids. Lignan is derived from tyrosine. Phenylalanine is converted to cinnamic acid by the enzyme phenylalanine ammonia-lyase; the genetic disorder phenylketonuria is the inability to metabolize phenylalanine because of a lack of the enzyme phenylalanine hydroxylase.
Individuals with this disorder are known as "phenylketonurics" and must regulate their intake of phenylalanine. Phenylketonurics use blood tests to monitor the amount of phenylalanine in their blood. Lab results may report phenylalanine levels using either mg/dL and μmol/L. One mg/dL of phenylalanine is equivalent to 60 μmol/L. A "variant form" of phenylketonuria called hyperphenylalaninemia is caused by the inability to synthesize a cofactor called tetrahydrobiopterin, which can be supplemented. Pregnant women with hyperphenylalaninemia may show similar symptoms of the disorder, but these indicators will disappear at the end of gestation. Pregnant women with PKU must control their blood phenylalanine levels if the fetus is heterozygous for the defective gene because the fetus could be adversely affected due to hepatic immaturity. A non-food source of phenylalanine is the artificial sweetener aspartame; this compound is metabolized by the body into several chemical byproducts including phenylalanine.
The breakdown problems phenylketonurics have with the buildup of phenylalanine in the body occurs with the ingestion of aspartame, although to a lesser degree. Accordingly, all products in Australia, the U. S. and Canada that contain aspartame must be labeled: "Phenylketonurics: Contains phenylalanine." In the UK, foods containing aspartame must carry ingredient panels that refer to the presence of "aspartame or E951" and they must be labeled with a warning "Contains a source of phenylalanine." In Brazil, the label "Contém Fenilalanina" is mandatory in products which contain it. These warnings are placed to help individuals avoid such foods. Geneticists sequenced the genome of macaques in 2007, their investigations found "some instances where the normal form of the macaque protein looked like the diseased human protein" including markers for PKU. The stereoisomer D-phenylalanine can be produced by conventional organic synthesis, either as a single enantiomer or as a component of the racemic mixture.
It does not participate in protein biosynthesis although it is found in proteins in small amounts - aged proteins and food proteins that have been processed. The biological functions of D-amino acids remain unclear, although D-phenylalanine has pharmacological activity at niacin receptor 2. DL-Phenylalanine is marketed as a nutritional supplement for its purported analgesic and antidepressant activ
Propane is a three-carbon alkane with the molecular formula C3H8. It compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is used as a fuel. Propane is one of a group of liquefied petroleum gases; the others include butane, butadiene, butylene and mixtures thereof. Propane was discovered by the French chemist Marcellin Berthelot in 1857, it was first identified as a volatile component in gasoline by Walter O. Snelling of the U. S. Bureau of Mines in 1910. Although the compound was known long before this, Snelling's work was the beginning of the propane industry in the United States; the volatility of these lighter hydrocarbons caused them to be known as "wild" because of the high vapor pressures of unrefined gasoline. On March 31, 1912, The New York Times reported on Snelling's work with liquefied gas, saying "a steel bottle will carry enough gas to light an ordinary home for three weeks", it was during this time that Snelling, in cooperation with Frank P. Peterson, Chester Kerr, Arthur Kerr, created ways to liquefy the LP gases during the refining of gasoline.
Together, they established American Gasol Co. the first commercial marketer of propane. Snelling had produced pure propane by 1911, on March 25, 1913, his method of processing and producing LP gases was issued patent #1,056,845. A separate method of producing LP gas through compression was created by Frank Peterson and its patent granted on July 2, 1912; the 1920s saw increased production of LP gas, with the first year of recorded production totaling 223,000 US gallons in 1922. In 1927, annual marketed LP gas production reached 1 million US gallons, by 1935, the annual sales of LP gas had reached 56 million US gallons. Major industry developments in the 1930s included the introduction of railroad tank car transport, gas odorization, the construction of local bottle-filling plants; the year 1945 marked the first year. By 1947, 62% of all U. S. homes had been equipped with either natural propane for cooking. In 1950, 1,000 propane-fueled buses were ordered by the Chicago Transit Authority, by 1958, sales in the U.
S. had reached 7 billion US gallons annually. In 2004, it was reported to be a growing $8-billion to $10-billion industry with over 15 billion US gallons of propane being used annually in the U. S; the "prop-" root found in "propane" and names of other compounds with three-carbon chains was derived from "propionic acid", which in turn was named after the Greek words protos and pion. Propane is produced as a by-product of two other processes, natural gas processing and petroleum refining; the processing of natural gas involves removal of butane and large amounts of ethane from the raw gas, in order to prevent condensation of these volatiles in natural gas pipelines. Additionally, oil refineries produce some propane as a by-product of cracking petroleum into gasoline or heating oil; the supply of propane cannot be adjusted to meet increased demand, because of the by-product nature of propane production. About 90% of U. S. propane is domestically produced. The United States imports about 10% of the propane consumed each year, with about 70% of that coming from Canada via pipeline and rail.
The remaining 30% of imported propane comes to the United States from other sources via ocean transport. After it is separated from the crude oil, North American propane is stored in huge salt caverns. Examples of these are Alberta; these salt caverns were hollowed out in the 1940s, they can store 80,000,000 barrels or more of propane. When the propane is needed, much of it is shipped by pipelines to other areas of the United States; the North American standard grade of automotive use propane is rated HD 5. HD 5 grade has a maximum of 5 percent butane, but propane sold in Europe, has a max allowable amount of butane of 30 percent, meaning it's not the same fuel as HD 5; the LPG used as auto fuel and cooking gas in Asia and Australia has a high content of butane. Propane is shipped by truck, ship and railway to many U. S. areas. Propane can be produced as a biofuel. Biopropane is commercially sold in Europe. Propane undergoes combustion reactions in a similar fashion to other alkanes. In the presence of excess oxygen, propane burns to form carbon dioxide.
When not enough oxygen or too much oxygen is present for complete combustion, incomplete combustion occurs, allowing carbon monoxide and/or soot to be formed as well: Complete combustion of propane produces about 50 MJ/kg of heat. Propane combustion is much cleaner than that of unleaded gasoline. Propane per BTU production of CO2 is as low as that of natural gas. Propane burns hotter than home heating oil or diesel fuel because of the high hydrogen content; the presence of C–C bonds, plus the multiple bonds of propylene and butylene, create organic exhausts besides carbon dioxide and water vapor during typical combustion. These bonds cause propane to burn with a visible flame; the enthalpy of combustion of propane gas where all products return to standard state, for example where water returns to its liquid state at standard temperature, is kJ/mol, or MJ/kg. The enthalpy of combustion of propane gas where products do not return to standard state, for example where the hot gases including water vapor exit a chimney, is −2043.455 kJ/mol.
The lower heat value is the amount of heat available from burning the substance where
Diethyl ether, or ether, is an organic compound in the ether class with the formula 2O, sometimes abbreviated as Et2O. It is a colorless volatile flammable liquid, it is used as a solvent in laboratories and as a starting fluid for some engines. It was used as a general anesthetic, until non-flammable drugs were developed, such as halothane, it has been used as a recreational drug to cause intoxication. Most diethyl ether is produced as a byproduct of the vapor-phase hydration of ethylene to make ethanol; this process uses solid-supported phosphoric acid catalysts and can be adjusted to make more ether if the need arises. Vapor-phase dehydration of ethanol over some alumina catalysts can give diethyl ether yields of up to 95%. Diethyl ether can be prepared both in laboratories and on an industrial scale by the acid ether synthesis. Ethanol is mixed with a strong acid sulfuric acid, H2SO4; the acid dissociates in the aqueous environment producing hydronium ions, H3O+. A hydrogen ion protonates the electronegative oxygen atom of the ethanol, giving the ethanol molecule a positive charge: CH3CH2OH + H3O+ → CH3CH2OH2+ + H2OA nucleophilic oxygen atom of unprotonated ethanol displaces a water molecule from the protonated ethanol molecule, producing water, a hydrogen ion and diethyl ether.
CH3CH2OH2+ + CH3CH2OH → H2O + H+ + CH3CH2OCH2CH3This reaction must be carried out at temperatures lower than 150 °C in order to ensure that an elimination product is not a product of the reaction. At higher temperatures, ethanol will dehydrate to form ethylene; the reaction to make diethyl ether is reversible, so an equilibrium between reactants and products is achieved. Getting a good yield of ether requires that ether be distilled out of the reaction mixture before it reverts to ethanol, taking advantage of Le Chatelier's principle. Another reaction that can be used for the preparation of ethers is the Williamson ether synthesis, in which an alkoxide performs a nucleophilic substitution upon an alkyl halide, it is important as a solvent in the production of cellulose plastics such as cellulose acetate. Diethyl ether has a high cetane number of 85–96 and is used as a starting fluid, in combination with petroleum distillates for gasoline and Diesel engines because of its high volatility and low flash point.
Ether starting fluid is sold and used in countries with cold climates, as it can help with cold starting an engine at sub-zero temperatures. For the same reason it is used as a component of the fuel mixture for carbureted compression ignition model engines. In this way diethyl ether is similar to one of its precursors, ethanol. Diethyl ether is a common laboratory aprotic solvent, it has limited solubility in water and dissolves 1.5 g/100 g water at 25 °C. This, coupled with its high volatility, makes it ideal for use as the non-polar solvent in liquid-liquid extraction; when used with an aqueous solution, the diethyl ether layer is on top as it has a lower density than the water. It is a common solvent for the Grignard reaction in addition to other reactions involving organometallic reagents. Due to its application in the manufacturing of illicit substances, it is listed in the Table II precursor under the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances as well as substances such as acetone and sulfuric acid.
William T. G. Morton participated in a public demonstration of ether anesthesia on October 16, 1846 at the Ether Dome in Boston, Massachusetts. However, Crawford Williamson Long, is now known to have demonstrated its use as a general anesthetic in surgery to officials in Georgia, as early as March 30, 1842, Long publicly demonstrated ether's use as a surgical anesthetic on six occasions before the Boston demonstration. British doctors were aware of the anesthetic properties of ether as early as 1840 where it was prescribed in conjunction with opium. Diethyl ether supplanted the use of chloroform as a general anesthetic due to ether's more favorable therapeutic index, that is, a greater difference between an effective dose and a toxic dose. Diethyl ether increases tracheobronchial secretions. Diethyl ether could be mixed with other anesthetic agents such as chloroform to make C. E. mixture, or chloroform and alcohol to make A. C. E. Mixture. In the 21st century, ether is used; the use of flammable ether was displaced by nonflammable fluorinated hydrocarbon anesthetics.
Halothane was the first such anesthetic developed and other used inhaled anesthetics, such as isoflurane and sevoflurane, are halogenated ethers. Diethyl ether was found to have undesirable side effects, such as post-anesthetic nausea and vomiting. Modern anesthetic agents reduce these side effects. Prior to 2005 it was on the World Health Organization's List of Essential Medicines for use as an anesthetic. Ether was once used in pharmaceutical formulations. A mixture of alcohol and ether, one part of diethyl ether and three parts of ethanol, was known as "Spirit of ether", Hoffman's Anodyne or Hoffman's Drops. In the United States this concoction was removed from the Pharmacopeia at some point prior to June 1917, as a study published by William Procter, Jr. in the American Journal of Pharmacy as early as 1852 showed that there were differences in formulation to be found between commercial manufacturers, between international pharmacopoeia, from Hoffman's original recipe. The anesthetic and intoxicating effects of ether have made it a recreational drug.
Diethyl ether in anesthetic dosage is an inhalant which has a long history
A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. Molecules are distinguished from ions by their lack of electrical charge. However, in quantum physics, organic chemistry, biochemistry, the term molecule is used less also being applied to polyatomic ions. In the kinetic theory of gases, the term molecule is used for any gaseous particle regardless of its composition. According to this definition, noble gas atoms are considered molecules as they are monatomic molecules. A molecule may be homonuclear, that is, it consists of atoms of one chemical element, as with oxygen. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are not considered single molecules. Molecules as components of matter are common in organic substances, they make up most of the oceans and atmosphere. However, the majority of familiar solid substances on Earth, including most of the minerals that make up the crust and core of the Earth, contain many chemical bonds, but are not made of identifiable molecules.
No typical molecule can be defined for ionic crystals and covalent crystals, although these are composed of repeating unit cells that extend either in a plane or three-dimensionally. The theme of repeated unit-cellular-structure holds for most condensed phases with metallic bonding, which means that solid metals are not made of molecules. In glasses, atoms may be held together by chemical bonds with no presence of any definable molecule, nor any of the regularity of repeating units that characterizes crystals; the science of molecules is called molecular chemistry or molecular physics, depending on whether the focus is on chemistry or physics. Molecular chemistry deals with the laws governing the interaction between molecules that results in the formation and breakage of chemical bonds, while molecular physics deals with the laws governing their structure and properties. In practice, this distinction is vague. In molecular sciences, a molecule consists of a stable system composed of two or more atoms.
Polyatomic ions may sometimes be usefully thought of as electrically charged molecules. The term unstable molecule is used for reactive species, i.e. short-lived assemblies of electrons and nuclei, such as radicals, molecular ions, Rydberg molecules, transition states, van der Waals complexes, or systems of colliding atoms as in Bose–Einstein condensate. According to Merriam-Webster and the Online Etymology Dictionary, the word "molecule" derives from the Latin "moles" or small unit of mass. Molecule – "extremely minute particle", from French molécule, from New Latin molecula, diminutive of Latin moles "mass, barrier". A vague meaning at first; the definition of the molecule has evolved. Earlier definitions were less precise, defining molecules as the smallest particles of pure chemical substances that still retain their composition and chemical properties; this definition breaks down since many substances in ordinary experience, such as rocks and metals, are composed of large crystalline networks of chemically bonded atoms or ions, but are not made of discrete molecules.
Molecules are held together by ionic bonding. Several types of non-metal elements exist only as molecules in the environment. For example, hydrogen only exists as hydrogen molecule. A molecule of a compound is made out of two or more elements. A covalent bond is a chemical bond; these electron pairs are termed shared pairs or bonding pairs, the stable balance of attractive and repulsive forces between atoms, when they share electrons, is termed covalent bonding. Ionic bonding is a type of chemical bond that involves the electrostatic attraction between oppositely charged ions, is the primary interaction occurring in ionic compounds; the ions are atoms that have lost one or more electrons and atoms that have gained one or more electrons. This transfer of electrons is termed electrovalence in contrast to covalence. In the simplest case, the cation is a metal atom and the anion is a nonmetal atom, but these ions can be of a more complicated nature, e.g. molecular ions like NH4+ or SO42−. An ionic bond is the transfer of electrons from a metal to a non-metal for both atoms to obtain a full valence shell.
Most molecules are far too small to be seen with the naked eye. DNA, a macromolecule, can reach macroscopic sizes, as can molecules of many polymers. Molecules used as building blocks for organic synthesis have a dimension of a few angstroms to several dozen Å, or around one billionth of a meter. Single molecules cannot be observed by light, but small molecules and the outlines of individual atoms may be traced in some circumstances by use of an atomic force microscope; some of the largest molecules are supermolecules. The smallest molecule is the diatomic hydrogen, with a bond length of 0.74 Å. Effective molecular radius is the size; the table of permselectivity for different substances contains examples. The chemical formula for a molecule uses one line of chemical element symbols and sometimes al
Imperial Chemical Industries
Imperial Chemical Industries was a British chemical company and was, for much of its history, the largest manufacturer in Britain. It was formed by the merger of leading British chemical companies in 1926, its headquarters were at Millbank in London, it was a constituent of the FT 30 and the FTSE 100 indices. ICI made paints and speciality products, including food ingredients, speciality polymers, electronic materials and flavourings. In 2008, it was acquired by AkzoNobel, which sold parts of ICI to Henkel, integrated ICI's remaining operations within its existing organisation; the company was founded in December 1926 from the merger of four companies: Brunner Mond, Nobel Explosives, the United Alkali Company, British Dyestuffs Corporation. It established its head office at Millbank in London in 1928. Competing with DuPont and IG Farben, the new company produced chemicals, fertilisers, dyestuffs, non-ferrous metals, paints. In its first year turnover was £27 million. In the 1920s and 30s, the company played a key role in the development of new chemical products, including the dyestuff phthalocyanine, the acrylic plastic Perspex, Dulux paints and polyethylene terephthalate fibre known as Terylene.
In 1940, ICI started British Nylon Spinners as a joint venture with Courtaulds. ICI owned the Sunbeam motorcycle business, which had come with Nobel Industries, continued to build motorcycles until 1937. During the Second World War, ICI was involved with the United Kingdom's nuclear weapons programme codenamed Tube Alloys. In the 1940s and 50s, the company established its pharmaceutical business and developed a number of key products, including Paludrine, Inderal, PEEK. ICI formed ICI Pharmaceuticals in 1957. ICI developed a fabric in the 1950s known as Crimplene, a thick polyester yarn used to make a fabric of the same name; the resulting cloth is heavy and wrinkle-resistant, retains its shape well. The California-based fashion designer Edith Flagg was the first to import this fabric from Britain to the USA. During the first two years, ICI gave Flagg a large advertising budget to popularise the fabric across America. In 1960, Paul Chambers became the first chairman appointed from outside the company.
Chambers employed the consultancy firm McKinsey to help with reorganising the company. His eight-year tenure saw export sales double, but his reputation was damaged by a failed takeover bid for Courtaulds in 1961–62. In 1962, ICI developed the controversial herbicide, paraquat. ICI was confronted with the nationalisation of its operations in Burma on 1 August 1962 as a consequence of the military coup. In 1964, ICI acquired British Nylon Spinners, the company it had jointly set up in 1940 with Courtaulds. ICI surrendered its 37.5 per cent holding in Courtaulds and paid Courtaulds £2 million a year for five years, "to take account of the future development expenditure of Courtaulds in the nylon field." In return, Courtaulds transferred to ICI their 50 per cent holding in BNS. BNS was absorbed into ICI Fibres; the acquisition included BNS production plants in Pontypool and Doncaster, together with research and development in Pontypool. Early pesticide development included Gramoxone, the insecticides pirimiphos-methyl in 1967 and pirimicarb in 1970, brodifacoum was developed in 1974.
Peter Allen was appointed chairman between 1968 and 1971. He presided over the purchase of Viyella. Profits shrank under his tenure. Jack Callard was appointed chairman from 1971 to 1975, he doubled company profits between 1972 and 1974, made ICI Britain's largest exporter. In 1971, the company acquired Atlas Chemical Industries Inc. a major American competitor. In 1977, Imperial Metal Industries was divested as an independent quoted company. From 1982 to 1987, the company was led by the charismatic John Harvey-Jones. Under his leadership, the company acquired the Beatrice Chemical Division in 1985 and Glidden Coatings & Resins, a leading paints business, in 1986. In 1991, ICI sold the agricultural and merchandising operations of BritAg and Scottish Agricultural Industries to Norsk Hydro, fought off a hostile takeover bid from Hanson, who had acquired 2.8 percent of the company. It divested its soda ash products arm to Brunner Mond, ending an association with the trade that had existed since the company's inception, one, inherited from the original Brunner, Mond & Co. Ltd.
In 1992, the company sold its nylon business to DuPont. In 1993, the company de-merged its pharmaceutical bio-science businesses: pharmaceuticals, specialities and biological products were all transferred into a new and independent company called Zeneca. Zeneca subsequently merged with Astra AB to form AstraZeneca. Charles Miller Smith was appointed CEO in 1994, one of the few times that someone from outside ICI had been appointed to lead the company, Smith having been a director at Unilever. Shortly afterwards, the company acquired a number of former Unilever businesses in an attempt to move away from its historical reliance on commodity chemicals. In 1995, ICI acquired the American paint company Grow Group. In 1997, ICI acquired National Starch & Chemical, Quest International and Crosfield, the speciality chemicals businesses of Unilever for $8 billion; this step was part of a strategy to move away