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Iso-butane [(CH3)3CH] can be isolated from the petroleum C4 fraction or from natural gas by extraction and distillation. There are two major uses of iso-butane. One is dehydrogenation to isobutylene followed by conversion of the isobutylene to the gasoline additive methyl t-butyl ether (MTBE). However, current environmental issues may ban this gasoline additive. Iso-butane is also oxidized to the hydroperoxide and then reacted with propylene to give propylene oxide and t-butyl alcohol. The t-butyl alcohol can be used as a gasoline additive, or dehydrate to iso-butylene.

Liquid paint is a dispersion of a finely divided pigment in a liquid (the vehicle) composed of a resin or binder and a volatile solvent (Fig. 1). The pigment, although usually an inorganic substance, may also be a pure, insoluble organic dye known as a toner, or an organic dye precipitated on an inorganic carrier such as aluminum hydroxide, barium sulfate, or clay, thus constituting a lake.
The solid particles in the paint reflect many of the destructive light rays, and thus help to prolong the life of the paint. In general, pigments should be opaque to ensure good covering power and chemically inert to secure stability, hence long life.

Soaps are the sodium or potassium salts of certain fatty acids obtained from the hydrolysis of triglycerides.

Fat + NaOH → glycerol + R–CO2 –Na+

Soap comprises the sodium or potassium salts of various fatty acids, but chiefly of oleic, stearic, palmitic, lauric, and myristic acids.

Manufacturing processes are both batch (in which the triglyceride is steam-hydrolyzed to the fatty acid without strong caustic, and then in a separate step it is converted into the sodium salt) or continuous.

The manufacture of soap (Fig. 1) involves continuous splitting (hydrolysis) and, after separation of the glycerin, neutralization of the fatty acids to soap. The procedure is to split, or hydrolyze, the fat, and then, after separation from the glycerol (glycerin) to neutralize the fatty acids with a caustic soda solution:

(C17H35COO)3C3H5 + 3H2O → 3C17H35COOH + C3H5(OH)5

C17H35COOH + NaOH → C17H35COONa + H2O

In continuous, countercurrent splitting, the fatty oil is deaerated under a vacuum to prevent darkening by oxidation during processing. It is charged at a controlled rate to the bottom of the hydrolyzing tower through a sparge ring (Fig. 2). The oil in the bottom contacting section rises because of its lower density and extracts the small amount of fatty material dissolved in the aqueous glycerol (glycerin) phase. At the same time, deaerated, demineralized water is fed to the top contacting section, where it extracts the glycerol dissolved in the fatty phase. After leaving the contacting sections, the two streams enter the reaction zone where they are brought to reaction temperature by the direct injection of high-pressure steam, and then the final phases of splitting occur. The fatty acids are discharged from the top of the splitter or hydrolyzer to a decanter, where the entrained water is separated or flashed off. The glycerol-water solution is then discharged from the bottom of an automatic interface controller to a settling tank.

Zinc oxide (ZnO) is manufactured by oxidizing zinc vapor in burners in which the concentration of zinc vapor and the flow of air are controlled to produce the desired particle size and shape. The hot gases and particulate oxide or fume pass through tubular coolers, and then the zinc oxide is separated in a baghouse. The purity of the zinc oxide depends upon the source of the zinc vapor.

In the indirect process, zinc metal vapor for burning is produced in several ways, one of which involves horizontal retorts. Since the entire vapor is burned in a combustion chamber, the purity of the oxide depends on that of the zinc feed. Oxide of the highest purity requires special high-grade zinc, and less-pure products are made by blending in Prime Western and even scrap zinc. In the direct process, four or more firebrick furnaces having common walls are charged in cyclic fashion. Coal that is hot from the previous charge is first spread on the grate and, after ignition, a damp, well-blended mixture of zinc ore or zinc-containing material and coal is added. The bed is maintained in a reducing condition with carbon monoxide to produce zinc and lead, if present. Metal vapors are drawn into a chamber above the furnace, where combustion air oxidizes them to pigment. The hot pigmentgas stream enters a cooling duct common to the whole block and, in this way, the product becomes a uniform blend. Traveling-grate furnaces can also be employed. In this process, anthracite briquettes are fed to a depth of about 15 cm. After ignition by the previous charge, the coal briquettes are covered by ore/coal briquettes. The latter are dried with waste heat from the furnace. Zinc vapor evolves and burns in a combustion chamber, and the spent clinker falls into containers for removal. A pigment-grade zinc oxide rotary kiln uses high temperature to produce pigment-quality zinc oxide and makes possible higher recovery than a grate furnace.
Other processes include an electrothermic process, an electric-arc vaporizer process, and the slag fuming process. Zinc oxide, as an amphoteric material, reacts with acids to form zinc salts and with strong alkali to form zincates. In the vulcanization of rubber, the chemical role of zinc oxide is complex and the free oxide is required, probably as an activator. Zinc oxide reacts with organic acids to produce zinc soaps and also reacts with carbon dioxide in moist air to form oxycarbonate. Acidic gases, e.g., hydrogen sulfide, sulfur dioxide, and chlorine, react with zinc oxide, and carbon monoxide or hydrogen reduce it to the metal. At high temperatures, zinc oxide replaces sodium oxide in silicate glasses. An important biochemical property of the oxide is its fungicidal/mildewstatic action. It is also soluble in body fluids and soils. Zinc oxide of high purity is required for pharmaceutical, photoconductive, and certain other uses, and is manufactured by the indirect process. Less-pure zinc oxide is manufactured by the direct process, by which impure zinc oxide is reduced to zinc vapor that is then burned.

Sulfuric acid is produced from sulfur, oxygen and water via the contact process.

In the first step, sulfur is burned to produce sulfur dioxide.

(1) S(s) + O2(g) → SO2(g)

This is then oxidized to sulfur trioxide using oxygen in the presence of a vanadium(V) oxide catalyst.

(2) 2 SO2 + O2(g) → 2 SO3(g) (in presence of V2O5)

Finally the sulfur trioxide is treated with water (usually as 97-98% H2SO4 containing 2-3% water) to produce 98-99% sulfuric acid.

(3) SO3(g) + H2O(l) → H2SO4(l)

Note that directly dissolving SO3 in water is not practical due to the highly exothermic nature of the reaction, forming a corrosive mist instead of a liquid. Alternatively, SO3 can be absorbed into H2SO4 to produce oleum (H2S2O7), which may then be mixed with water to form sulfuric acid.

(3) H2SO4(l) + SO3 → H2S2O7(l)

Oleum is reacted with water to form concentrated H2SO4.

(4) H2S2O7(l) + H2O(l) → 2 H2SO4(l)

Aspirin (acetylsalicylic acid) is by far the most common type of analgesic, an important class of compounds that relieve pain, and it also lowers abnormally high body temperatures. Aspirin also finds use in reducing inflammation caused by rheumatic fever and rheumatoid arthritis. The manufacture of aspirin is based on the synthesis of salicylic acid from phenol. Reaction of carbon dioxide with sodium phenoxide is an electrophilic aromatic substitution on the ortho, para-directing phenoxy ring. The ortho isomer is steam distilled away from the para isomer. C6H5OH + CO2 → HOC6H4CO2H Salicylic acid reacts easily with acetic anhydride to give aspirin. HOC6H4CO2H + (CH3CO)2O → CH3OCOC6H4CO2H + CH3CO2H In this process, a 500-gallon glass-lined reactor is needed to heat the salicylic acid and acetic anhydride for 2 to 3 hours. The mixture is transferred to a crystallizing kettle and cooled to 3oC. Centrifuging and drying of the crystals yields the bulk aspirin. The excess solution is stored and the acetic acid is recovered to make more acetic anhydride. The irritation of the stomach lining caused by aspirin can be alleviated with the use of mild bases such as sodium bicarbonate, aluminum glycinate, sodium citrate, aluminum hydroxide, or magnesium trisilicate (a trademark for this type of aspirin is Bufferin®). Both phenacetin and the newer replacement acetaminophen are derivatives of p-aminophenol. Although these latter two are analgesics and antipyretics, the aniline-phenol derivatives show little if any anti-inflammatory activity. p-Aminophenol itself is toxic, but acylation of the amino group makes it a convenient drug. A trademark for acetaminophen is Tylenol®. Excedrin® is acetaminophen, aspirin, and caffeine. Acetaminophen is easily synthesized from phenol.

Acetone (dimethyl ketone, 2-propanone, CH3COCH3, melting point: –94.6oC, boiling point: 56.3oC, density: 0.783) is the simplest ketone and is a colorless liquid that is miscible in all proportions with water, alcohol, or ether. There are two major processes for the production of acetone (2-propanone). The feedstock for these is either iso-propyl alcohol [(CH3)2CHOH] or cumene [iso-propyl benzene, C6H5CH(CH3)2]. In the last few years there has been a steady trend away from iso-propyl alcohol and toward cumene, but iso-propyl alcohol should continue as a precursor since manufacture of acetone from only cumene would require a balancing of the market with the coproduct phenol from this process. Acetone is made from iso-propyl alcohol by either dehydrogenation (preferred) or air oxidation. These are catalytic processes at 500oC and 40 to 50 psi. The acetone is purified by distillation, boiling point 56oC and the conversion per pass is 70 to 85 percent, with the overall yield being in excess of 90 percent.
CH3CH(OH)CH3 → CH3C(=O)CH3 + H2 .2CH3CH(OH)
CH3 + O2 → CH3C(=O)CH3 + 2H2O
Cumene is also used as a feedstock for the production of acetone. In this process, cumene first is oxidized to cumene hydroperoxide followed by the decomposition of the cumene hydroperoxide into acetone and phenol. The hydroperoxide is made by reaction of cumene with oxygen at 110 to 115oC until 20 to 25 percent of the hydroperoxide is formed. Concentration of the hydroperoxide to 80% is followed by catalyzed rearrangement under moderate pressure at 70 to 100oC. During the reaction, the palladium chloride (PdCl2) catalyst is reduced to elemental palladium to produce hydrogen chloride that catalyzes the rearrangement, and reoxidation of the palladium is brought about by use of cupric chloride (CuCl2) that is converted to cuprous chloride (CuCl). The cuprous chloride is reoxidized during the catalyst regeneration cycle.The overall yield is 90 to 92 percent. By-products are acetophenone, 2-phenylpropan-2-ol, and α-methylstyrene. Acetone is distilled first at boiling point 56oC.
Vacuum distillation recovers the unreacted cumene and yields α−methylstyrene, which can be hydrogenated back to cumene and recycled. Further distillation separates phenol, boiling point 181oC, and acetophenone, boiling point 202oC.
In older industrial processes, acetone is prepared (1) by passing the vapors of acetic acid over heated lime. Calcium acetate is produced in the first step followed by a breakdown of the acetate into acetone and calcium carbonate:
CH3CO2H + CaO → (CH3CO2)2Ca + H2O (CH3CO2)2
Ca → CH3COCH3 + CaCO3
and (2) by fermentation of starches, such as maize, which produce acetone along with butyl alcohol. Acetone is a very important solvent and is widely used in the manufacture of plastics and lacquers. For storage purposes, acetone may be used as a solvent for acetylene. Acetone is the starting ingredient or intermediate for numerous organic syntheses. Closely related, industrially important compounds are diacetone alcohol [CH3COCH2COH(CH3)2], which is used as a solvent for cellulose acetate and nitrocellulose, as well as for various resins and gums, and as a thinner for lacquers and inking materials. Acetone is used for the production of methyl methacrylate, solvents, bisphenol A, aldol chemicals, and pharmaceuticals. Methyl methacrylate is manufactured and then polymerized to poly(methyl methacrylate), an important plastic known for its clarity and used as a glass substitute.
Aldol chemicals refer to a variety of substances desired from acetone involving an aldol condensation in a portion of their synthesis. The most important of these chemicals is methyl iso-butyl ketone (MIBK), a common solvent for many plastics, pesticides, adhesives, and pharmaceuticals. Bisphenol A is manufactured by a reaction between phenol and acetone, the two products from the cumene hydroperoxide rearrangement. Bisphenol A is an important diol monomer used in the synthesis of polycarbonates and epoxy resins. A product known as synthetic methyl acetone is prepared by mixing acetone (50%), methyl acetate (30%), and methyl alcohol (20%) and is used widely for coagulating latex and in paint removers and lacquers.