The present invention relates to the use of a transition metal catalyst TMC1, which comprises a transition metal M selected from metals of groups 7, 8, 9 and 10 of the periodic table of elements according to IUPAC and a tetradentate ligand of formula I wherein R.sup.1 are identical or different and are each an organic radical having from 1 to 40 carbon atoms, and R.sup.2 are identical or different and are each an organic radical having from 1 to 40 carbon atoms, as catalyst in processes for formation of compounds comprising at least one carboxylic acid ester functional group OC(O) starting from at least one primary alcohol and/or hydrogenation of compounds comprising at least one carboxylic acid ester functional group OC(O). The present invention further relates to a process for hydrogenation of a compound comprising at least one carboxylic acid ester functional group OC(O), to a process for the formation of a compound comprising at least one carboxylic acid ester functional group OC(O) by dehydrogenase coupling of at least one primary alcohol with a second alcoholic OH-group, to a transition metal complex comprising the tetradentate ligand of formula I and to a process for preparing said transition metal complex.

##STR00001##

The present invention relates to the use of a transition metal catalyst TMC1, which comprises a transition metal M selected from metals of groups 7, 8, 9 and 10 of the periodic table of elements according to IUPAC and a tetradentate ligand of formula I wherein R.sup.1 are identical or different and are each an organic radical having from 1 to 40 carbon atoms, and R.sup.2 are identical or different and are each an organic radical having from 1 to 40 carbon atoms, as catalyst in processes for formation of compounds comprising at least one carboxylic acid ester functional group OC(O) starting from at least one primary alcohol and/or hydrogenation of compounds comprising at least one carboxylic acid ester functional group OC(O). The present invention further relates to a process for hydrogenation of a compound comprising at least one carboxylic acid ester functional group OC(O), to a process for the formation of a compound comprising at least one carboxylic acid ester functional group OC(O) by dehydrogenase coupling of at least one primary alcohol with a second alcoholic OH-group, to a transition metal complex comprising the tetradentate ligand of formula I and to a process for preparing said transition metal complex.

##STR00001##

The invention comprises a process for the preparation of a chiral triol of formula I

##STR00001## wherein, R.sup.1 is hydrogen or halogen by way of an asymmetric hydrogenation of a ketone compound of formula IIa

##STR00002## wherein, R.sup.1 is hydrogen or halogen and R.sup.2 is C.sub.1-6-alkyl; with hydrogen in the presence of an iridium spiro-pyridylamidophosphine catalyst (Ir-SpiroPAP catalyst). The chiral triols of formula I are versatile building blocks for the preparation of various pharmaceutically active drug substances such as for instance for statins.

A method for preparing 1,4-cyclohexanedimethanol is provided. The method allows hydrogen gas fed into a reaction tank to be uniformly dispersed in a reaction solution by a gas-introducing mixer having air-extracting, air-exhausting and mixing functions. Accordingly, the reaction solution has a high concentration of dissolved hydrogen gas so that the reaction time of hydrogenation can be reduced to as short as possible. Furthermore, the method uses a hydrogenation catalyst having many advantages such as high activity and low cost. The added amount of the hydrogenation catalyst can be reduced under the operation of the gas-introducing mixer.

Certain embodiments are directed to an integrated process for the production of Maleic Anhydride (MAN), 1,4 Butanediol (BDO), Gamma-ButyroLactone (GBL), and PolyButylene Terephthalate (PBT) utilizing NC4 rich stream from a recycle stream after or before processing by a Total Hydrogenation Unit (THU).

Certain embodiments are directed to an integrated process for the production of Maleic Anhydride (MAN), 1,4 Butanediol (BDO), Gamma-ButyroLactone (GBL), and PolyButylene Terephthalate (PBT) utilizing NC4 rich stream from a recycle stream after or before processing by a Total Hydrogenation Unit (THU).

Provided is a method for preparing a lower unsaturated fatty acid ester, which comprises carrying out an aldol condensation reaction between dimethoxymethane (DMM) and a lower acid or ester with a molecular formula of R.sub.1CH.sub.2COOR.sub.2 on an acidic molecular sieve catalyst in an inert atmosphere to obtain a lower unsaturated fatty acid or ester(CH.sub.2C(R.sub.1)COOR.sub.2), wherein R.sub.1 and R.sub.2 are groups each independently selected from the group consisting of H- and C.sub.1-C.sub.4 saturated alkyl group.

Provided is a method for preparing a lower unsaturated fatty acid ester, which comprises carrying out an aldol condensation reaction between dimethoxymethane (DMM) and a lower acid or ester with a molecular formula of R.sub.1CH.sub.2COOR.sub.2 on an acidic molecular sieve catalyst in an inert atmosphere to obtain a lower unsaturated fatty acid or ester(CH.sub.2C(R.sub.1)COOR.sub.2), wherein R.sub.1 and R.sub.2 are groups each independently selected from the group consisting of H- and C.sub.1-C.sub.4 saturated alkyl group.

A process for the hydrogenation of a substrate comprising a carbon heteroatom double bond in the presence of a transition metal complex comprising a tridentate or bisdentate-ligand containing a nitrogen, sulphur and phosphorus atom, of which at least the N- and P- and optionally also the S-atom coordinates with the transition metal.

A process for the hydrogenation of a substrate comprising a carbon heteroatom double bond in the presence of a transition metal complex comprising a tridentate or bisdentate-ligand containing a nitrogen, sulphur and phosphorus atom, of which at least the N- and P- and optionally also the S-atom coordinates with the transition metal.