GB742642A - Dimerization of mono-olefins - Google Patents

Abstract

Mono-olefins of more than 2 carbon atoms are dimerized by heating at 60-250 DEG C. in the presence of an activator selected from the hydrides of Be, Al, Ga or In and derivatives thereof wherein one or more hydrogen atoms are substituted by alkyl or monovalent aromatic hydrocarbon radicals. Suitable activators are, for example: Be(C2H5)2, AlH3, HAl(CH3)2, H2AlC2H5, Al(CH3)3, Al(C2H5)3, Al(C6H5)3, Ga(CH3)3, In(CH3)3, Be(C6H5)2, Al(C6H13)3, Al(C18H37)3, Ga(C6H5)3 or In(C6H5)3. Molecular compounds with, for example, ethers, thioethers or amines, and complexes with alkali metal hydrides, alkyls or aryls may also be used, such as NaBe(C2H)3, LiAlH4, LiAl (C2H5)4 and NaAl(C6H5)4. a -Olefins up to octadecene-1 react readily to form dimers with isomers as by-products. Thus butene-1 gives a dibutene and butene-2, hexene-1 gives a dihexene and hexenes-2 and 3, and dodecene-1 a di-dodecene and dodecenes-2, 3, 4, 5 and 6. Dimerization of olefins with intermediate double bonds requires longer and is impracticable for olefins of more than 12 carbon atoms. Branched olefins and aryl substituted olefins such as <FORM:0742642/IV(a)/1> and <FORM:0742642/IV(a)/2> may also be treated. Mixtures of olefins may be used yielding both simple and mixed dimers. By choosing an activator such as aluminium trialkyl, the alkyl radical having the same number of C atoms as one olefin reactant, and adding the olefins in different sequence, different products may be produced. Inert materials, especially paraffins and aromatics, may be present. Cracked fractions from petroleum, e.g. C3-C6 cuts, may be converted to dimers which yield alcohols, aldehydes, and acids by oxo synthesis. Pressure may be employed, e.g. up to 2,000 atm. or more. Polymers may also be formed, for example, if heating is continued. In examples: (1) and (2) Al(C2H5)3 or Al(CH3)3, pentane, and propylene are heated in an autoclave at 180 DEG C. and initial pressure of 170 atm. giving mainly 1 - methyl - 1 - propyl - ethylene; (3) propylene and Al(CH3)3 under pressure are heated to 200 DEG C., raising the pressure to 170 atm.; (4) Al(C3H7)3 or Al(C6H5)3 is substituted for the activator of (1). Continuous reaction may be effected by passing a solution of the activator, about 10-20 per cent, in propylene under pressure into a heated reactor or tubular coil at 200-240 DEG C., the products leaving at the lower end being recovered, and propylene and activator recycled; (5) dodecene and Al(C2H5)3 etherate are heated at 230 DEG C.; (6) Be(C2H5)2 and propylene are autoclaved; (7) propylene and Al(C3H7)3 is passed down a heated coil under pressure; (8) pentene-1 and Al(C2H5)3 are autoclaved; (9) propylene, pentene-1, and AlH3 are autoclaved to yield a mixture of dimers.