Patent GB-581014-A (GB)
Title: Production of hydrocarbon alkylation products
IPC: C07C9/16
Filed: 1944-02-16
Abstract: A mixed alkylate of aromatic hydrocarbons with tertiary olefins, and isoparaffins with secondary olefins is blended with aviation base stock to give gasoline of high power output.  Thus a benzene-di-isobutene alkylate containing tertiary butyl benzene, and an isobutene-n-butene alkylate may be blended in equal volumes with 50 per cent. of base stock.  Addition of propene in the alkylation of benzene yields a mixed cumene, tertiary butyl benzene product which is similarly blended.ALSO:A mixture of secondary and tertiary olefins is treated with a strong inorganic polybasic acid to separate a tertiary olefin which is reacted with an aromatic hydrocarbon under alkylating conditions, the remaining secondary olefin being reacted with an isoparaffin in the presence of an alkylation catalyst. Sulphuric acid from the isoparaffin alkylation stage may be used for refining the aromatic hydrocarbon to be alkylated, for separating the olefins, and as catalyst for the aromatic alkylation. Secondary butenes and isobutane, preferably in a molar excess of at least 5 : 1, are reacted in the form of a circulating emulsion with sulphuric acid, preferably above 90 per cent.  Alkylate is separated and an n-butane fraction may be removed and is isomerized or dehydrogenated for use in the alkylation.  Part of the acid phase is mixed with benzene at about 20-50 DEG  C. for 5-15 mins., preferably using 0.1-0.25 vols./vol. of benzene, to remove sulphur compounds.  The acid is diluted to about 60-70 per cent, impurities separated, if desired by adding liquefied n-butane as a solvent, and then passed to an absorption unit where a C4 fraction is treated to absorb isobutene selectively.  The acid solution is heated to about 70-110 DEG  C. to produce polymers, advantageously in the presence of n-butane as a solvent, and the polymer fraction separated and used to alkylate the refined benzene, using sulphuric acid from the isoparaffin alkylation stage diluted to 80-90 per cent as catalyst.  A molar excess of benzene, e.g. 6-10 mols. per mol. of di-isobutene or 9-15 per mol. of triisobutene, a temperature of 40-50 DEG  C., contact time of 20-30 mins., and volume ratio of acid to hydrocarbon of 0.25-1.3 : 1 are suitable to yield tertiary butyl benzene.  The hydrocarbon phase may be treated at above 100 DEG  C. with a base while in liquid phase and the alkylate recovered.  Both alkylation stages may be effected with other catalysts such as phosphoric acid, hydrogen fluoride and aluminium chloride, catalyst from the isoparaffin alkylation stage preferably being used for the aromatic alkylation.  The polymerization of the tertiary olefin may be effected selectively or as a copolymerization with part of the secondary olefin or other olefins in one step or may be omitted.  Additional olefins such as propene may also take part in the alkylation of the aromatic hydrocarbon which may also be toluene, xylenes, ethyl, propyl or isopropyl benzene, mesitylene, cymene or naphthalene.  Other isoparaffins which may be alkylated by the secondary olefins include isopentane, isohexane and 2,3-dimethylbutane.  This alkylation may be effected in stages using the same or different olefins while catalyst from an earlier stage may be used in a later, for example, sulphuric acid from a butene or butene-propene alkylation may be used with pentenes.  In an example, a cracked C4 fraction is treated with diluted acid from isobutane alkylation and benzene treatment at 20 DEG  C. for 5 mins. using a ratio of 65 per cent acid to hydrocarbon of 0.1 : 1, absorbed isobutene is polymerized at 89 DEG  C. in presence of added butane, benzene is pretreated with alkylation acid of 92 per cent at 35 DEG  C., and alkylation of isobutane is effected with 98 per cent acid at 20 DEG  C. for 20 mins., and of benzene with 80 per cent acid at 50 DEG  C. for 30 mins.  The total alkylate is blended in equal volumes with an aviation base stock. Alternatively, a calcined phosphoric acid-clay catalyst is used for the benzene alkylation at 220-275 DEG  C. and 250 lbs./sq. in.