Method for producing alkyl-substituted butenols
View Patent ↗Alkyl-substituted butenols having the formula (I): R 1 —CH 2 —CH═CR 2 —CH 2 OH (I) wherein R 1 is a saturated or olefinically unsaturated alkyl or cycloalkyl group having from 4 to 16 carbon atoms and wherein R 1 is optionally substituted by an alkyl, cycloalkyl, aryl or alkaryl having up to 12 carbon atoms; R 2 is hydrogen or an alkyl group having from 1 to about 6 carbon atoms are produced by a process which comprises: (1) reacting an aldehyde of the formula (II): R 1 —CH 2 —CHO (II) wherein R 1 has the same meaning as in formula (I), with the corresponding lower aldehyde to form an unsaturated aldehyde in an inert organic solvent; (2) continuously contacting an optionally calcined copper/zinc catalyst with the unsaturated aldehyde under isothermal conditions at temperatures of from about 45 to about 60° C. and under a hydrogen pressure of from 1 to about 300 bar.
1. A process for the production of an alkyl-substituted butenol having the formula (I):
R 1 —CH 2 —CH═CR 2 —CH 2 OH (I)
wherein R 1 is a saturated or olefinically unsaturated alkyl or cycloalkyl group having from 4 to 16 carbon atoms and wherein R 1 is optionally substituted by an alkyl, cycloalkyl, aryl or alkaryl having up to 12 carbon atoms; and R 2 is hydrogen or an alkyl group having from 1 to about 6 carbon atoms the process comprising:
by reacting at least one aldehyde of the formula (II) with at least one corresponding lower aldehyde:
R 1 —CH 2 —CHO (II)
and R 1 has the same meaning as in formula (I);
wherein:
(i) aldol condensation is carried out in an inert organic solvent, and
(ii) reduction of the unsaturated aldehydes is carried out in the presence of an optionally calcined copper/zinc catalyst, and is carried out continuously under isothermal conditions at a temperature ranging from 45 to 60° C. and under a hydrogen pressure of 1 to 300 bar at an LHSV (liquid hourly space velocity) of 0.3 to 3.0 hr −1 .
2. The process of claim 1 , wherein the aldol condensation is carried out in a nonpolar organic solvent which can form an azeotrope with water.
3. The process of claim 1 , wherein the aldol condensation is carried out in the presence of a catalyst which is an ammonium salt of an organic acid.
4. The process of claim 1 , wherein R 2 in formula (I) is a methyl group.
5. The process of claim 1 , wherein R 2 in formula (I) is a methyl group and wherein propionaldehyde is used in a 2.5 to 10-fold molar excess based on the aldehyde of formula (II).
6. The process of claim 5 , wherein the propionaldehyde is used in a 2.5 to 3.5-fold molar excess based on the aldehyde of formula (II).
7. The process of claim 1 wherein R 1 is a 4-(2,2,3-trimethylcyclopent-3-en-1-yl) group.
8. The process of claim 1 , wherein the organic solvent in (i) is selected from the group consisting of toluene, xylene, benzene, cyclohexane and methyl cyclohexane.
9. The process of claim 1 , wherein R 1 is a saturated alkyl group having from 4 to 16 carbon atoms.
10. The process of claim 1 , wherein R 1 is an olefinically unsaturated alkyl group having from 4 to 16 carbon atoms.
11. The process of claim 1 , wherein R 1 is an olefinically unsaturated cycloalkyl group having from 4 to 16 carbon atoms.
12. The process of claim 1 , wherein R 1 is not further substituted.
13. The process of claim 1 , wherein R 1 is substituted by an alkyl, cycloalkyl, aryl or alkaryl having up to 12 carbon atoms.
14. The process of claim 1 , wherein R 2 is hydrogen.
15. The process of claim 1 , wherein R 2 is an alkyl group having from 2 to 6 carbon atoms.
16. The process of claim 1 , wherein said LHSV (liquid hourly space velocity) ranges from 0.6 to 1.2 hr −1 .
17. A process for the production of an alkyl-substituted butenol having the formula (I):
R 1 —CH 2 —CH═CR 2 —CH 2 OH (I)
wherein R 1 is a saturated or olefinically unsaturated alkyl or cycloalkyl group having from 4 to 16 carbon atoms and wherein R 1 is optionally substituted by an alkyl, cycloalkyl, aryl or alkaryl having up to 12 carbon atoms; and R 2 is hydrogen or an alkyl group having from 1 to about 6 carbon atoms the process comprising:
by reacting at least one aldehyde of the formula (II) with at least one corresponding lower aldehyde:
R 1 —CH 2 —CHO (II)
and R 1 has the same meaning as in formula (I);
wherein:
(i) aldol condensation is carried out in an inert organic solvent, and
(ii) reduction of the unsaturated aldehydes is carried out in the presence of an optionally calcined copper/zinc catalyst, and
is carried out continuously in a fixed bed reactor at a LHSV (liquid hourly space velocity) of 0.3 to 3.0 hr −1 ,
under isothermal conditions at a temperature ranging from 45 to 60° C., and
under a hydrogen pressure of 1 to 300 bar.