C-2-butene

C-2-Butene Product information Quality code 2.0 Purity % volume >99 Impurities ppm (where nothing else stated) Trans-2-Butene <0.5% O2 <10 N2 <50 General information Filling pressure at 15 C, bar: 1.5Material recommendations:Gas: No restrictions.Liquid: Avoid plastic and rubber. Characteristics Highly flammable, liquefied, colourless gas. Health risks Asphyxiating. Transport ADR Class 2, 3(b). Physical data Molecular weight: 56.11Boiling point at 1.013 bar,C: 3.72Density (1.013 bar, 15 C) kg/m3: 2.46Vapour pressure at 0 C, bar: 0.8820 C, bar: 1.8Flammability range in air, % (volume): 1.7-9.7Specific volume (1.013 bar, 15 C), m3/kg: 0.407 Source Almost all commercially produced butenes are obtained as by-products from two principal processes: Catalytic or thermal cracking, refinery processes which upgrade high boiling petroleum fractions to gasoline, and Steam cracking, which produces light olefins for chemical feed stocks by pyrolysis of saturated hydrocarbons derived from natural gas or crude oil. The butenes obtained are withdrawn as a mixture from the C4-fraction. From this mixture butadiene and butanes are separated by extractive distillation. The remaining butenes cannot be separated by mere distillation because their boiling points are too close together. In a first step iso-butene is isolated either by etherification with methanol to form methyl tert- butylether (MTB), or by hydrating iso-butene to tert-butanol (TBA). In this step all other C4 components in the mixture remain unchanged. MTB and TBA can then be split by reversing synthesis to produce high purity iso-butene. Once the iso-butene content has been reduced, recovery of high purity 1-butene is possible by fractionation. The remaining 2-butenes can be separated by molecular sieve absorption methods. Other commercial processes that are sometimes used to produce specific isomers or mixtures of butenes or both, either directly or as by-products, include: The oxirane process for making propylene oxide (-> iso-butene)The dehydrogenation of butane and iso-butane (-> 1-butene, cis-2-butene, trans-2- butene)The disproportionation of olefins (-> cis-2-butene, trans-2-butene) The oligomerization of ethylene (-> 1-butene). All or any of them may become useful feedstock sources should the need arise. Applications Cis-2-Butene is a member of-the alkene group of hydrocarbons. Alkenes serve as intermedi-ates in the preparation of a variety of organic compounds. Sulfuric acid and sulfur dioxide react with alkenes to give alkyl hydrogen sulfates and alkyl sulfonates, respectively, many of which are useful as detergents. In the industrially important Oxo process, alkenes react catalytically with carbon monoxide and hydrogen to give aldehydes. Alkenes are polymer ized by heating with catalysts to give high-octane gasolines, plastics, and synthetic rubber. Alkanes react with alkenes in the presence of catalysts to form motor fuels in a process known as alkylation. Cis-2-Butene is a chemical intermediate in the following processes: Catalytic dehydrogenation to produce butadieneThe addition of water by means of the acid sulfate leads to the formation of 2-butanolEsterification in the presence of tungstic acid, followed by oxidation by oxygen or air, in the liquid phase, leads to the production of acetic acidAcetic acid can also be produced through oxidation by oxygen or air in the presence of manganese acetate in the liquid phaseCondensation of iso-butane with butenes leads to the formation of 2,2,3-trimethyl pentane, a high octane fuelCis-2.-Butene is also employed as a solvent.