The present invention relates to a catalyst system for preparing a carbonate derivative, comprising selenium (Se) and a pyridine amine compound represented by structural formula 1. The catalyst system for preparing a carbonate derivative, and a method for preparing a carbonate derivative by using same, of the present invention, allow an alcohol to undergo oxidative carbonylation by using a selenium-based catalyst system, and thus are more economical than a conventional carbonylation process and can obtain a dialkyl carbonate in feasible yields.

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 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##

A method for preparing methyl methacrylate from methacrolein and methanol. The method comprises contacting a mixture comprising methacrolein, methanol and oxygen with a heterogeneous catalyst comprising a support and a noble metal, wherein oxygen concentration at a reactor outlet is from 1 to 7.5 mol % and wherein pH at a reactor outlet is no greater than 7.5.

A method for preparing methyl methacrylate from methacrolein and methanol. The method comprises contacting a mixture comprising methacrolein, methanol and oxygen with a heterogeneous catalyst comprising a support and a noble metal, wherein oxygen concentration at a reactor outlet is from 1 to 7.5 mol % and wherein pH at a reactor outlet is no greater than 7.5.

Provided is a process for preparing methacrolein which maximizes capture of methanol. Also provided are processes for producing methacrylic acid and methyl methacrylate.

Provided is a process for preparing dry methacrolein which maximizes capture of methanol. Also provided is a process for producing methyl methacrylate.

A method for preparing methyl methacrylate from methacrolein and methanol. The method comprises contacting a mixture comprising methacrolein, methanol and oxygen with a heterogeneous catalyst comprising a support and a noble metal, wherein said catalyst has an average diameter of at least 200 microns and average concentration of methacrolein is at least 15 wt %.

A method for preparing methyl methacrylate from methacrolein and methanol. The method comprises contacting a mixture comprising methacrolein, methanol and oxygen with a heterogeneous catalyst comprising a support and a noble metal, wherein said catalyst has an average diameter of at least 200 microns and average concentration of methacrolein is at least 15 wt %.