摘要:
The present invention provides a process for preparing a (1,2-dimethyl-3-methylenecyclopentyl)acetate compound of the following general formula (3), wherein R represents a linear or branched alkyl group having 1 to 4 carbon atoms, the process comprising subjecting a haloacetaldehyde alkyl 2,3-dimethyl-2-cyclopentenyl acetal compound of the following general formula (1), wherein R is as defined above, and Y represents a halogen atom, to a dehydrohalogenation reaction in the presence of a base, followed by a rearrangement reaction to obtain a (1,2-dimethyl-2-cyclopentenyl)acetate compound of the following general formula (2), wherein R is as defined above, and subjecting the (1,2-dimethyl-2-cyclopentenyl)acetate compound (2) to an epoxidation reaction, followed by an isomerization reaction and then a methylenation reaction to obtain the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound of the following general formula (3). The present invention also provides a process for preparing (1,2-dimethyl-3-methylenecyclopentyl)acetaldehyde of the following formula (4), the process comprising the aforesaid process for preparing the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound (3), and converting an alkoxycarbonylmethyl group (i.e., -CH 2 C(=O)OR) of the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound (3) to a formylmethyl group (i.e., -CH 2 CHO) to obtain (1,2-dimethyl-3-methylenecyclopentyl)acetaldehyde (4).
摘要:
The present invention provides processes for preparing an α-necrodyl compound of the following general formula (3): wherein R 2 represents a monovalent hydrocarbon group having 1 to 9 carbon atoms, the process comprising: subjecting a 3, 5, 5-trimethyl-3-cyclopentene compound of the following general formula (1): wherein R 2 is as defined above, and X represents a leaving group, to a nucleophilic substitution reaction with a methylating agent of the following general formula (2): wherein M represents Li, MgZ 1 , ZnZ 1 , Cu, CuZ 1 , or CuLiZ 1 , and Z 1 represents a halogen atom or a methyl group, to form the α-necrodyl compound (3). The present invention further provides processes for preparing γ-necrodyl compounds of the following general formula (4): wherein R 2 represents a monovalent hydrocarbon group having 1 to 9 carbon atoms, the process comprising: subjecting the α-necrodyl compound (3) thus obtained to a positional isomerization reaction at the double bond to form the γ-necrodyl compound (4).
摘要:
The present invention relates to a carbon-based precious metal-transition metal composite catalyst and a preparation method therefor, and more particularly, to a catalyst synthesis method in which, when preparing a high-content precious metal-transition metal composite catalyst, a catalyst having uniform particles and composition can be prepared, and cyclohexane dimethanol (CHDM) is efficiently produced by the hydrogenation reaction of cyclohexane dicarboxylic acid (CHDA) in an aqueous solution. Provided is a method for preparing a carbon-based precious metal-transition metal composite catalyst, wherein, in the carbon-based precious metal-transition metal composite catalyst, the precious metal is included in an amount of 10-20 parts by weight, and the transition metal is included in an amount of 10-20 parts by weight based on 100 parts by weight of the composite catalyst, and thus a total amount of the precious metal-transition metal is 20-40 parts by weight based on 100 parts by weight of the composite catalyst.
摘要:
The present disclosure relates to a method for preparation of 1,4-cyclohexanedimethanol. According to the present disclosure, two step reduction reactions are conducted using terephthalic acid as starting material, and an isomerization process for increasing the rate of trans isomers of CHDA is introduced therebetween, thereby providing a method capable of stably preparing CHDM with high rate of trans isomers.
摘要:
The present invention relates to a method for regenerating a dicarboxylic acid or carboxylic acid hydrogenation catalyst, and more particularly, to a method for regenerating a hydrogenation catalyst to be used in a reaction of converting a dicarboxylic acid group into a diol group. The present invention provides an effect of regenerating a catalyst deactivated by the deposition of esters to be produced in a reaction of converting a dicarboxylic acid group into a diol group.
摘要:
The present invention provides a process for preparing 2-isopropenyl-5-methyl-4-hexenoic acid of the following formula (4), comprising steps of: subjecting a Grignard reagent of the following general formula (1), wherein R 1 represents a linear, branched, or aromatic monovalent hydrocarbon group having 1 to 8 carbon atoms, and X represents a chlorine atom, a bromine atom, or an iodine atom, and 1,1,1,3,3,3-hexamethyldisilazane to a deprotonation reaction to form a 1,1,1,3,3,3-hexamethyldisilazane derivative; and subjecting 2-methyl-3-buten-2-yl 3-methyl-2-butenoate of the following formula (3) to a rearrangement reaction in the presence of the 1,1,1,3,3,3-hexamethyldisilazane derivative to form 2-isopropenyl-5-methyl-4-hexenoic acid (4).