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Isobutylene (or 2-methylpropene) is a hydrocarbon with the chemical formula (CH 3) 2 C=CH 2. It is a four-carbon branched alkene (olefin), one of the four isomers of butylene . It is a colorless flammable gas, and is of considerable industrial value.
Butyl rubber, sometimes just called "butyl", is a synthetic rubber, a copolymer of isobutylene with isoprene. The abbreviation IIR stands for isobutylene isoprene rubber. Polyisobutylene, also known as "PIB" or polyisobutene, (C 4 H 8) n, is the homopolymer of isobutylene, or 2-methyl-1-propene, on which butyl rubber is based. Butyl rubber is ...
Isobutylene can be produced through a variety of methods. n-butane can be isomerized into isobutane which can be dehydrogenated to isobutylene. [7] In the Halcon process, t-Butyl hydroperoxide derived from isobutane oxygenation is treated with propylene to produce propylene oxide and t-butanol. The t-butanol can be dehydrated to isobutylene.
The tert-butyl substituent is very bulky and is used in chemistry for kinetic stabilization, as are other bulky groups such as the related trimethylsilyl group. The effect of the tert-butyl group on the progress of a chemical reaction is called the Thorpe–Ingold effect illustrated in the Diels-Alder reaction below.
Illustrative is the conversion of isobutylene to tert-butylamine using HCN and sulfuric acid followed by base neutralization. The weight of the salt byproduct is greater than the weight of the amine. [12] In the laboratory, the Ritter reaction suffers from the necessity of an extremely strong acid catalyst.
The reaction conditions for the synthesis of each type of isobutylene product vary depending on the desired molecular weight and what type(s) of monomer(s) is used. The conditions most commonly used to form low molecular weight (5–10 x 10 4 Da) polyisobutylene are initiation with AlCl 3, BF 3, or TiCl 4 at a temperature range of −40 to 10 ...
Butene, also known as butylene, is an alkene with the formula C 4 H 8.The word butene may refer to any of the individual compounds. They are colourless gases that are present in crude oil as a minor constituent in quantities that are too small for viable extraction.
Polyisobutene (polyisobutylene) is a class of organic polymers prepared by polymerization of isobutene.The polymers often have the formula Me 3 C[CH 2 CMe 2] n H (Me = CH 3).They are typically colorless gummy solids.