摘要:
An improved process for the production of chloroprene, which is the critical monomer constituent of neoprene rubbers, and of 2,3-dichlorobutadiene-1,3, which often is copolymerized with chloroprene to provide better low temperature properties of the resulting elastomer, involves dehydrochlorination of a chlorinated hydrocarbon such as 3,4-dichlorobutene-1, 2,3,4-trichlorobutene-1, or 1,2,3,4-tetrachlorobutane, with an aqueous mixture of sodium hydroxide and sodium chloride having the composition of chlor/alkali cell liquor; separation of the organic phase from which the desired product, chloroprene or 2,3-dichlorobutadiene-1,3, is recovered by distillation; and recirculation of the aqueous (brine) phase to the electrolysis apparatus, from which the sodium hydroxide-sodium chloride liquor is returned to the dehydrochlorination step. This process saves energy in that it does not require cell liquor concentration to isolate pure sodium hydroxide, and it is environmentally desirable because it avoids problems associated with brine disposal.
摘要:
Formation of solid and/or high boiling residues during the isomerization of one of 1,4-dichlorobutene-2 and 3,4-dichlorobutene-1 into each other in the presence of a cuprous chloride catalyst is inhibited by the addition to the isomerization reaction of a small amount of a hydroxylamine salt.
摘要:
Liquid phase chlorination in an evaporatively cooled reactor of 1,3-butadiene to 3,4-dichlorobutene-1 and 1,4-dichlorobutene-2 by contacting 1,3-butadiene and elemental chlorine in a solvent at a temperature of 25.degree.-100.degree. C. said solvent being butane or pentane or a fluorinated solvent of the formula (CR.sub.3)(CR'.sub.2).sub.m (CR".sub.2).sub.n R where R is independently hydrogen, fluorine, chlorine or bromine, R' is hydrogen, R" is independently fluorine, chlorine or bromine, m and n are 0-3 with the proviso that terminal carbon atoms are independently perhalogenated or fully hydrogenated, the solvents boil at -15.degree. C. to 40.degree. C. at atmospheric pressure, and the solvent to dichlorobutene ratio is from 2.0:1 to 11:1. The heat of reaction is removed by vaporization of solvent and 1,3-butadiene and returning the ingredients to the reactor.
摘要:
Molecular chlorine level in flue gases from incineration of chlorinated organic materials is reduced by injecting into the incinerator's quench zone an amount of a C.sub.1 -C.sub.4 hydrocarbon which depends on the amount of air fed into the combustion zone, the amount of air being such that there is a 1-40 % excess of oxygen. When the wall temperature of the combustion zone is about 800.degree.-1500.degree. C., the temperature at which the hydrocarbon is added to the quench zone is about 450.degree.-1000.degree. C. Hydrogen chloride, which is formed from molecular chlorine and hydrocarbon, is more readily water-scrubbed than chlorine, so that less polluting flue gases are obtained.
摘要:
Chlorinated organic compounds from the aqueous waste streams from a process for manufacturing and isomerizing dichlorobutenes and dehydrochorinating 3,4-dichlorobutene-1 to chloroprene, which is the principal monomer in the manufacture of neoprene rubber, are removed by means of a process, wherein the aqueous waste from the dichlorobutene-isomerization step and brine formed in the dehydrochlorination step are combined to produce an aqueous solution containing about 1-5% sodium chloride and the solution, while maintained at a pH of less than about 6, is extracted with a small amount of a liquid hydrocarbon. The liquid hydrocarbon extract is then incinerated, while the extracted aqueous solution is discharged into a natural body of water. In this way, the level of 1,4-dichlorobutene-2, which is toxic to fish, in the natural body of water can be maintained at a safe level.