Gasoline polymers, manufacture

In general, NIR papers did not begin in earnest until the 1970s, when commercial instruments became easily available because of the work of the US Department of Agriculture (USDA)[8-12], Some of these developments will be discussed in Section 6.3. After the success of the USD A, food producers, chemical producers, polymer manufacturers, gasoline producers, etc. picked up the ball and ran with it. The last to become involved, mainly for regulatory reasons, are the pharmaceutical and biochemical industries. 

Huoroelastomers are fluorine containing hydrocarbon polymers manufactured under various tradenames such as Viton by DuPont, Technoflon by Ausimont, and Fluorel by 3M. The fluoroelastomers provide excellent resistance to oils, fuels, lubricants, most mineral acids, many aliphatic and aromatic hydrocarbons (carbon tetrachloride, benzene, toluene, xylene) that act as solvents for rubbers, gasoline, naphtha, chlorinated solvents, and pesticides. 

Sulfuric acid is used as a catalyst in gasoline, jet fuel, and polymer manufacture. The sulfuric acid catalyst is not consumed, but it becomes ineffective as it absorbs water, hydrocarbons, and other chemicals over time. Its catalytic properties are maintained by bleeding off some of the contaminated spent acid and regenerating it to high purity 98% H2S04( ) sulfuric acid. 

Examples of nir analysis are polymer identification (126,127), pharmaceutical manufacturing (128), gasoline analysis (129,130), and on-line refinery process chemistry (131). Nir fiber optics have been used as immersion probes for monitoring pollutants in drainage waters by attenuated total internal reflectance (132). The usefulness of nir for aqueous systems has led to important biological and medical appHcations (133). 

This combination of monomers is unique in that the two are very different chemically, and in thek character in a polymer. Polybutadiene homopolymer has a low glass-transition temperature, remaining mbbery as low as —85° C, and is a very nonpolar substance with Htde resistance to hydrocarbon fluids such as oil or gasoline. Polyacrylonitrile, on the other hand, has a glass temperature of about 110°C, and is very polar and resistant to hydrocarbon fluids (see Acrylonitrile polymers). As a result, copolymerization of the two monomers at different ratios provides a wide choice of combinations of properties. In addition to providing the mbbery nature to the copolymer, butadiene also provides residual unsaturation, both in the main chain in the case of 1,4, or in a side chain in the case of 1,2 polymerization. This residual unsaturation is useful as a cure site for vulcanization by sulfur or by peroxides, but is also a weak point for chemical attack, such as oxidation, especially at elevated temperatures. As a result, all commercial NBR products contain small amounts ( 0.5-2.5%) of antioxidant to protect the polymer during its manufacture, storage, and use. 

Used industrially as a chemical intermediate in the manufacture of pesticides and phos-phosilicate glass. Used as a gasoline additive, catalyst, and as a fireproofing agent in the production of textiles and flame-retardant polymers for polyurethane foams. 

Potential exposure to butadiene can occur in the following industrial activities petroleum refining and related operations (production of C4 fractions containing butadiene, and production and distribution of gasoline), production of purified butadiene monomer, production of various butadiene-based rubber and plastics polymers and other derivatives, and manufacture of rubber and plastics products (tyres, hoses and a variety of moulded objects). 

Unsaturated hydrocarbons are important industrial raw materials in the manufacture of chemicals and polymers. Moreover, they are valuable constituents in high-octane gasoline produced mainly through cracking of larger alkanes, although, as... 

C4 Alkenes. Several industrial processes have been developed for olefin production through catalytic dehydrogenation138 166 167 of C4 alkenes. All four butenes are valuable industrial intermediates used mostly for octane enhancement. Isobutylene, the most important isomer, and its dimer are used to alkylate isobutane to produce polymer and alkylate gasoline (see Section 5.5.1). Other important utilizations include oxidation to manufacture maleic anhydride (see Section 9.5.4) and hydroformylation (see Section 7.1.3). 

Benzene and many of its derivatives are manufactured on a large scale for use in high-octane gasolines and in the production of polymers, insecticides, detergents, dyes, and many miscellaneous chemicals. Prior to World War II, coal was the only important source of aromatic hydrocarbons, but during the war and thereafter, the demand for benzene, methylbenzene, and the dimethyl-benzenes rose so sharply that other sources had to be found. Today, most of tbe benzene and almost all of the methylbenzene and the dimethylbenzenes produced in the United States are derived from petroleum. 

Although aviation gasoline can be made by the alkylation of isobutane with propylene, butylenes, and amylenes, the butylenes are by far the predominant feed. In a few cases a mixture of di- and triisobutylene polymers, which is a byproduct of butadiene manufacture, is used as part of the olefinic charge. Either sulfuric acid or hydrofluoric acid can be used as a catalyst when aviation gasoline is produced by the alkylation reaction. 

Use Manufacture of isopropyl alcohol, polypropylene, synthetic glycerol, acrylonitrile, propylene oxide, heptene, cumene, polymer gasoline, acrylic acid, vinyl resins, oxo chemicals. 

Propylene. Unlike ethylene, propylene production does not represent the requirement for propylene derivatives. With few exceptions, propylene is not made on purpose but is obtained as a by-product of other processes. More specifically, large quantities of relatively low purity (40-70%) propylene are produced in refineries as a by-product of gasoline manufacture. Additionally, significant quantities of higher purity propylene originate in olefins plants, where ethylene is the primary product. However, only polymer-grade propylene (>99% pure) can in any way be considered an on-purpose product. To better understand... 

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