Disclosed is a chemical process of preparing dehydrohedione from Hedione via α-chlorination and elimination steps. The process can be conducted in a one-pot process or in a continuous reactor system. Accordingly, a simple and cost effective process of preparing cis-Hedione enriched products is developed through reduction of dehydrohedione in the presence of a chiral catalyst system.

Disclosed is a chemical process of preparing dehydrohedione from Hedione via α-chlorination and elimination steps. The process can be conducted in a one-pot process or in a continuous reactor system. Accordingly, a simple and cost effective process of preparing cis-Hedione enriched products is developed through reduction of dehydrohedione in the presence of a chiral catalyst system.

Provided is a hydrogenation method of a phthalate compound. According to the present invention, in the hydrogenation reaction, generation of by-products is suppressed, and thus catalytic activity is improved and life-time is extended, thereby increasing efficiency of a commercial process and economic efficiency. Further, since the hydrogenation product prepared by the present invention has high purity and a low acid value, its quality as a plasticizer is excellent, thereby being applied to a variety of products.

Provided is a hydrogenation method of a phthalate compound. According to the present invention, in the hydrogenation reaction, generation of by-products is suppressed, and thus catalytic activity is improved and life-time is extended, thereby increasing efficiency of a commercial process and economic efficiency. Further, since the hydrogenation product prepared by the present invention has high purity and a low acid value, its quality as a plasticizer is excellent, thereby being applied to a variety of products.

Provided is a hydrogenation method of a phthalate compound. According to the present invention, in the hydrogenation reaction, generation of by-products is suppressed, and thus catalytic activity is improved and life-time is extended, thereby increasing efficiency of a commercial process and economic efficiency. Further, since the hydrogenation product prepared by the present invention has high purity and a low acid value, its quality as a plasticizer is excellent, thereby being applied to a variety of products.

There is provided a novel optically active bisphosphinomethane useful as a ligand for an asymmetric catalyst, excellent in oxidation resistance in air, and easy in handling. There is also provided a transition metal complex using the optically active bisphosphinoraethane having excellent asymmetric catalytic ability as a ligand. The optically active bisphosphinomethane is represented by the general formula (1), and the transition metal complex has the optically active bisphosphinomethane as a ligand.

##STR00001##

(In the formula, R.sup.1 represents an adamantyl group; R.sup.2 represents a branched alkyl group having 3 or more carbon atoms; and * represents an asymmetric center on a phosphorus atom.)

There is provided a novel optically active bisphosphinomethane useful as a ligand for an asymmetric catalyst, excellent in oxidation resistance in air, and easy in handling. There is also provided a transition metal complex using the optically active bisphosphinoraethane having excellent asymmetric catalytic ability as a ligand. The optically active bisphosphinomethane is represented by the general formula (1), and the transition metal complex has the optically active bisphosphinomethane as a ligand.

##STR00001##

(In the formula, R.sup.1 represents an adamantyl group; R.sup.2 represents a branched alkyl group having 3 or more carbon atoms; and * represents an asymmetric center on a phosphorus atom.)

The invention provides a process for regenerating a catalyst used for the hydrogenation of an aromatic species, consisting of several steps. First the system is purged with nitrogen, then air is metered in stepwise, and the addition of nitrogen is subsequently ended until only air is present.

The invention provides a process for regenerating a catalyst used for the hydrogenation of an aromatic species, consisting of several steps. First the system is purged with nitrogen, then air is metered in stepwise, and the addition of nitrogen is subsequently ended until only air is present.

The invention provides a process for regenerating a catalyst used for the ring hydrogenation of an aromatic species, especially an aromatic ester, wherein a gas stream containing a particular amount of oxygen is used for the regeneration.