Method for making trans non-conjugated diolefins
AssigneeExxon Chemical Patents Inc.
InventorsRobert Scott Smith, Jos Peter Wristers
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Abstract
A method is provided for selectively producing a trans-geometrical isomer of non-conjugated diolefins. The method comprises treating a starting non-conjugated diolefin isomer or mixture of isomers, a first mono-olefin and a second mono-olefin with a metathesis catalyst under selected reaction conditions to produce a product with greater than 80% trans-geometrical isomer content. In a preferred embodiment, 1,4-hexadiene, ethene, and propene contact a Re.sub.2 O.sub.7 catalyst and are converted to a reaction product mixture with above 80% trans-1,4-hexadiene.
Claims20
A method for making trans non-conjugated diolefins of structure ##STR8## where N is a positive integer from 1 to 5 and R.sup.2, R.sup.3, and R.sup.4 are each hydrogen or an alkyl of 1 to 5 carbons and R.sup.1 is an alkyl of 1 to 5 carbons
- which comprises:
- a. selecting isomerizable non-conjugated diolefin with structure ##STR9## where N is a positive integer from 1 to 5 and R.sup.2, R.sup.3, R.sup.4 and R.sup.5, are each hydrogen or an alkyl of 1 to 5 carbons and R.sup.1 and R.sup.6 are each an alkyl of 1 to 5 carbons and R.sup.2, R.sup.3, and R.sup.4 are the same as in the trans non-conjugated diolefin and when R.sup.5 is hydrogen and R.sup.6 is an alkyl, the adjacent double bond is greater than 50% cis;
- b. selecting a first olefin from the group consisting of:
- (1) olefins having the structure ##STR10## (2) olefins having the structure:
- ##STR11## and (3) mixtures of olefin 1 and olefin 2 where R.sup.1 is the same as R.sup.1 of the trans non-conjugated diolefin;
- c. selecting a second olefin which is different than the first olefin from the group consisting of
- (1) an olefin having the structure:
- ##STR12## (2) an olefin having the structure:
- ##STR13## and (3) mixtures of olefin 1 and olefin 2 where R.sup.3 and R.sup.4 are the same as R.sup.3 and R.sup.4 of the diolefin selected in step a;
- d. mixing the selected diolefin with the selected first olefin and the selected second olefin in a mole ratio of first olefin to diolefin within the range of about 0.2/1 to 100/1 and a mole ratio of the selected second olefin to diolefin within the range of about 0.2/1 to 100/1 to form an olefin reaction mixture;
- and
- e. contacting the olefin reaction mixture in a reaction vessel at a temperature in the range of -30.degree. to 200.degree. C. at a pressure in the range of 140 to 2,000 psig (1,070 to 14,000 kPa) with a non-acidic metathesis catalyst selected from the group consisting of homogeneous metal catalysts and heterogeneous metal catalysts wherein the metal is selected from the group consisting of W, Mo, Co, Ta, Nb, Cr, and Re to form the selected trans nonconjugated diolefin isomer product.
A method of preparing trans-1,4-hexadiene consisting essentially of contacting an olefin reaction feed mixture comprising cis-1,4-hexadiene, ethane and an olefin selected from the group consisting of propane, 2-butane, and mixtures of propene and 2-butene, under effective conditions with a metathesis catalyst which comprises one or more compounds selected from the group consisting of rhenium oxide (Re.sub.2 O.sub.7), tungsten oxide (WO.sub.3), cobalt oxide (CoO), or molybdenum oxide (MoO.sub.3);
- the selected catalyst compound being loaded onto a solid support at a loading of between 5 and 30 wt % in a fixed catalyst bed.
Dependencies are inferred from the claim text.