Patent GB-983376-A (GB)
Title: Process for the production of detergent alkylate
Inventor: OLDHAM WILFRED JOHN
IPC: B01J23/34
Filed: 1962-10-16
Abstract: A detergent alkylate, produced from propylene by two-fold catalytic dimerisation and condensation of the product with an aromatic hydrocarbon, in which a normal hexene fraction is separated from the first dimerisation and used in the second dimerization and a C10-C16 fraction is separated from the second dimerisation and catalytically condensed with an aromatic hydrocarbon (see Division C5), may be sulphonated in known manner.  Examples 1 and 2 in conjunction illustrate the condensation of a dimer of normal hexene, prepared and separated as described, with benzene to form a detergent alkylate which is sulphonated in conventional manner and converted to the sodium salt.ALSO:A detergent alkylate is produced from propylene by two-fold catalytic dimerisation, and condensation of the product with an aromatic hydrocarbon; from the first dimerization a normal hexene fraction is separated and used in the second dimerization, and from this step a fraction in the C10 to C16 carbon number range, extending over a range of not more than 5 carbon numbers, is separated and catalytically condensed with an aromatic hydrocarbon.  The feed may be pure propylene or a C3 fraction from which acetylenes and propadiene have been removed by selective hydrogenation. Dimerization is effected at 20-150 DEG  C. and under sufficient pressure to maintain the reactants in the liquid phase, and preferred catalysts are the oxides of transition metals for example Ni, Co, Cr, particularly Ni, optionally on a carrier such as silica, silica gel or preferably silica-alumina. An inert solvent, e.g. a C5 paraffin may be used.  The conversion of propylene is preferably incomplete, e.g. 30-80%. The dimerization product may then be fractionally distilled in three stages, unconverted propylene (and propane if present) being initially removed and recycled, a methyl pentene fraction predominating in 4-methyl-2-pentene then being removed and finally a distillate containing the required normal hexenes being recovered.  (Isoprene may be produced from the recovered methyl pentene by double bond isomerization and cracking.)  The dimerization of the normal hexenes involves similar temperatures, pressures and degree of conversion to those for dimerization of propylene; as catalyst a transition metal oxide \sB carrier, or alternatively a higher polymerization catalyst or a synthetic petroleum cracking catalyst e.g. silica-alumina may be used; however, manganese oxide is preferred.  In one embodiment the feed hexenes include added straight chain C5 to C8 mono-olefines from an external source.  The second dimerization product may be fractionally distilled in two stages, unchanged normal hexenes being first removed and recycled, and a fraction containing C10 to C16 molecules being recovered in the second stage.  In a preferred embodiment only normal hexene dimers (C12) are recovered. The recovered fraction is condensed at - 20 DEG to + 100 DEG  C. in the liquid phase with benzene, toluene, naphthalene or a xylene in the presence of an alkylation catalyst such as aluminium chloride or anhydrous hydrogen flouride.  Benzene and hydrogen fluoride are the preferred materials.  A distillate detergent alkylate fraction is recovered by fractionation, after separation of the catalyst.  The product may be sulphonated in known manner (see Division C2).