Composition and process for separation of trialkylaluminum compounds

• Main Authors: POE RONALD L, WILLIAMS BILLY J
• Format: Patent
• Language: English
• Published: 27.06.1967
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAININGELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN,SULFUR, SELENIUM OR TELLURIUM; CHEMISTRY; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; METALLURGY; ORGANIC CHEMISTRY; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ARTCOLLECTIONS [XRACs] AND DIGESTS

To either (A) a displacement product containing low molecular weight trialkyl aluminium and a -olefin or (B) a mixture of non-olefin hydrocarbon and a low molecular weight trialkyl aluminium or (C) a mixture of a dialkyl aluminium alkoxide and a low molecular weight trialkyl aluminium or (D) mixtures of any of these is added a complexing agent for the low molecular weight trialkylaluminium comprising either a compound RnMX or a complex of RnMX and low molecular weight trialkyl aluminium in a 1 : 1 ratio, in an amount sufficient to form a complex having a 2 : 1 ratio of trialkyl aluminium to RnMX with substantially all of the trialkyl aluminium, and separating the 2 : 1 complex. R is an alkyl radical, M is nitrogen, arsenic, phosphorus, sulphur, selenium or tellurium, X is halogen and n is 3 or 4. The complexing agent is preferably a tetra-alkyl ammonium halide or a 1 : 1 complex thereof with low molecular weight tri-alkyl aluminium, and complexes a (R13Al)R4NCl, wherein R1 i an alkyl radical containing 2-5 carbon atoms, R contains 1-5 carbon atoms, and a is 1 or 2 are claimed per se. The complexing reaction takes place at 50-150 DEG C., suitably at atmospheric pressure during a time of 0.25-30 minutes. In the formation of the 1 : 1 complex, equimolar amounts of the reactants or a slight excess of trialkyl aluminium are employed. In the reaction between the 1 : 1 complex and trialkyl aluminium, preferably an excess, e.g. 1.05 to 1.2 moles of 1 : 1 complex per mole of trialkyl aluminium is employed. The displacement product may be that obtained by treating a high molecular weight trialkyl aluminium in which the alkyl radicals have an average of 4 to 30 carbon atoms with an a -olefin containing 2 to 5 carbon atoms and this may be treated with a 1 : 1 complex of a tetra-alkyl ammonium halide in which the alkyl radicals have an average of 1 to 5 carbon atoms and a trialkyl aluminium in which the alkyl radicals have an average of 2 to 5 carbon atoms. A lower layer of 2 : 1 complex so produced is separated and washed with a paraffinic hydrocarbon containing 5-12 carbon atoms. The 2 : 1 complex may be decomposed at least partly to 1 : 1 complex and trialkyl aluminium by heating at subatmospheric pressure, but decomposition is preferably achieved by contacting the complex with a non-reactive extraction solvent, e.g. a hydrocarbon having 4 to 20 carbon atoms, at 100-200 DEG C. under atmospheric pressure. The hydrocarbon is conveniently the same as that used in the growth reaction, e.g. kerosene. In a continuous reaction the complex and 1 to 40 volumes of solvent are contacted in countercurrent in an extraction zone during a residence time of 1 to 60 minutes and extraction solvent enriched in trialkyl aluminium and complex material enriched in 1 : 1 complex are withdrawn from the zone. Part of the latter may be returned to the extraction zone. The remainder is recycled to the complexing stage.