Methods or preparing para-xylene from biomass by carrying out a Diels-Alder cycloaddition at controlled temperatures and activity ratios. Methods of preparing bio-terephthalic acid and bio-poly(ethylene terephthalate (bio-PET) are also disclosed, as well as products formed from bio-PET.

Methods or preparing para-xylene from biomass by carrying out a Diels-Alder cycloaddition at controlled temperatures and activity ratios. Methods of preparing bio-terephthalic acid and bio-poly(ethylene terephthalate (bio-PET) are also disclosed, as well as products formed from bio-PET.

Processes of forming C.sub.sp2C.sub.sp3 bonds at the allylic carbon of a cyclic allylic compound starting material are disclosed, in which a racemic mixture of a cyclic allylic compound having a leaving group attached to the allylic carbon is reacted with a compound having a nucleophilic carbon atom in the presence of a Rh(I), Pd(II) or Cu(I) pre-catalyst and a chiral ligand. The reaction products containing the newly-formed C.sub.sp2C.sub.sp3 bond are generated in high stereoisomeric excess, and may therefore serve as important organic building blocks in the preparation of new agrochemicals and pharmaceuticals.

Processes of forming C.sub.sp2C.sub.sp3 bonds at the allylic carbon of a cyclic allylic compound starting material are disclosed, in which a racemic mixture of a cyclic allylic compound having a leaving group attached to the allylic carbon is reacted with a compound having a nucleophilic carbon atom in the presence of a Rh(I), Pd(II) or Cu(I) pre-catalyst and a chiral ligand. The reaction products containing the newly-formed C.sub.sp2C.sub.sp3 bond are generated in high stereoisomeric excess, and may therefore serve as important organic building blocks in the preparation of new agrochemicals and pharmaceuticals.

The invention relates to an N-heterocyclic carbene complex of general formulas I to IV (I) (II) (III) (IV), according to which A1 stands for NR2 or PR2, A2 stands for CR2 R2, NR2, PR2, 0 or S, A3 stands for N or P, and C stands for a carbene carbon atom, ring B is an unsubstituted or a mono or poly-substituted 5 to 7-membered ring, substituents R2 and R2 stand, inter alia, for a linear or branched C1-Cw-alkyl group and, if N and N each stand for NR2 or PR2, are the same or different, M in formulas I, II, III or IV stands for Cr, Mo or W, X 1 or X2 in formulas I to IV are the same or different and represent, inter alia, C1-C1s carboxylates and C1-C1s-alkoxides, Y is inter alia oxygen or sulphur, Z is inter alia a linear or branched C1-Cw-alkylenoxy group, and R 1 and R1 in formulas I to IV are, inter alia, an aliphatic or aromatic group. These compounds are particularly suitable for use as catalysts for olefin metathesis reactions and have the advantage, compared to known Schrock carbene complexes, of displaying clearly increased tolerance to functional groups such as, in particular, aldehydes, secondary amines, nitriles, carboxylic acids and alcohols.

The invention relates to an N-heterocyclic carbene complex of general formulas I to IV (I) (II) (III) (IV), according to which A1 stands for NR2 or PR2, A2 stands for CR2 R2, NR2, PR2, 0 or S, A3 stands for N or P, and C stands for a carbene carbon atom, ring B is an unsubstituted or a mono or poly-substituted 5 to 7-membered ring, substituents R2 and R2 stand, inter alia, for a linear or branched C1-Cw-alkyl group and, if N and N each stand for NR2 or PR2, are the same or different, M in formulas I, II, III or IV stands for Cr, Mo or W, X 1 or X2 in formulas I to IV are the same or different and represent, inter alia, C1-C1s carboxylates and C1-C1s-alkoxides, Y is inter alia oxygen or sulphur, Z is inter alia a linear or branched C1-Cw-alkylenoxy group, and R 1 and R1 in formulas I to IV are, inter alia, an aliphatic or aromatic group. These compounds are particularly suitable for use as catalysts for olefin metathesis reactions and have the advantage, compared to known Schrock carbene complexes, of displaying clearly increased tolerance to functional groups such as, in particular, aldehydes, secondary amines, nitriles, carboxylic acids and alcohols.

A method for preparing a ruthenium catalyst, including a step of reducing a ruthenium catalyst precursor by holding the ruthenium catalyst precursor in an aqueous solution containing a metal salt at a temperature within the range of more than 180 C. and 220 C. or less and a hydrogen partial pressure within the range of 0.6 MPa or more and 5 MPa or less. A method for producing a cycloolefin, including a step of preparing a ruthenium catalyst by the method including a step of reducing a ruthenium catalyst precursor in an aqueous solution containing a metal salt by holding the ruthenium catalyst precursor at a temperature within the range of more than 180 C. and 220 C. or less and a hydrogen partial pressure within the range of 0.6 MPa or more and 5 MPa or less, and a step of partially hydrogenating a monocyclic aromatic hydrocarbon by use of the ruthenium catalyst obtained.

A method for preparing a ruthenium catalyst, including a step of reducing a ruthenium catalyst precursor by holding the ruthenium catalyst precursor in an aqueous solution containing a metal salt at a temperature within the range of more than 180 C. and 220 C. or less and a hydrogen partial pressure within the range of 0.6 MPa or more and 5 MPa or less. A method for producing a cycloolefin, including a step of preparing a ruthenium catalyst by the method including a step of reducing a ruthenium catalyst precursor in an aqueous solution containing a metal salt by holding the ruthenium catalyst precursor at a temperature within the range of more than 180 C. and 220 C. or less and a hydrogen partial pressure within the range of 0.6 MPa or more and 5 MPa or less, and a step of partially hydrogenating a monocyclic aromatic hydrocarbon by use of the ruthenium catalyst obtained.

The present invention relates to a new method to produce 7,8-dihydro-C.sub.15-aldehyde.

The present invention relates to a new method to produce 7,8-dihydro-C.sub.15-aldehyde.