The invention concerns a synthesis process of a compound of the following formula (I) or one of the salts thereof,

##STR00001## wherein R represents a COOH, CH.sub.2OH or CHO group, comprising the step according to which the but-3-ene-1,2-diol (BDO) is subjected to an oxidation in the presence of a catalyst, said catalyst comprising an active phase based on at least one noble metal selected from palladium, gold, silver, platinum, rhodium, osmium, ruthenium and iridium, and a support containing alkaline sites.

The invention also concerns the application of this reaction to the preparation of bioavailable compounds of methionine used, in particular, in animal nutrition.

The invention concerns a synthesis process of a compound of the following formula (I) or one of the salts thereof,

##STR00001## wherein R represents a COOH, CH.sub.2OH or CHO group, comprising the step according to which the but-3-ene-1,2-diol (BDO) is subjected to an oxidation in the presence of a catalyst, said catalyst comprising an active phase based on at least one noble metal selected from palladium, gold, silver, platinum, rhodium, osmium, ruthenium and iridium, and a support containing alkaline sites.

The invention also concerns the application of this reaction to the preparation of bioavailable compounds of methionine used, in particular, in animal nutrition.

A continuous flow process for the preparation of one or more esters of lactic acid and 2-hydroxy-3-butenoic acid or α-hydroxy methionine analogues from a sugar in the presence of a solid Lewis acid catalyst and a solvent comprising an organic solvent and water. The invention provides a means for stabilizing a Lewis acid catalyst for use in a continuous reaction process wherein the water is present in an amount of up to or equal to 10 vol. % of the organic solvent.

A continuous flow process for the preparation of one or more esters of lactic acid and 2-hydroxy-3-butenoic acid or α-hydroxy methionine analogues from a sugar in the presence of a solid Lewis acid catalyst and a solvent comprising an organic solvent and water. The invention provides a means for stabilizing a Lewis acid catalyst for use in a continuous reaction process wherein the water is present in an amount of up to or equal to 10 vol. % of the organic solvent.

A continuous flow process for the preparation of one or more esters of lactic acid and 2-hydroxy-3-butenoic acid or α-hydroxy methionine analogues from a sugar in the presence of a solid Lewis acid catalyst and a solvent comprising an organic solvent and water. The invention provides a means for stabilizing a Lewis acid catalyst for use in a continuous reaction process wherein the water is present in an amount of up to or equal to 10 vol. % of the organic solvent.

The present invention discloses high pressure flow reactor vessels and associated systems. Also disclosed are processes for producing thiol compounds and sulfide compounds utilizing these flow reactor vessels.

The present invention discloses high pressure flow reactor vessels and associated systems. Also disclosed are processes for producing thiol compounds and sulfide compounds utilizing these flow reactor vessels.

Derivatives of an organic substance containing one or more groups selected from the group consisting of sulfanyl, selanyl and sulfino may be produced by reacting an organic substance containing one or more groups selected from the group consisting of sulfanyl, selanyl and sulfino with an olefin compound containing an ethylene structure having at least two electron-withdrawing groups except halogen atoms under an acidic condition to form a derivative of the organic substance

Derivatives of an organic substance containing one or more groups selected from the group consisting of sulfanyl, selanyl and sulfino may be produced by reacting an organic substance containing one or more groups selected from the group consisting of sulfanyl, selanyl and sulfino with an olefin compound containing an ethylene structure having at least two electron-withdrawing groups except halogen atoms under an acidic condition to form a derivative of the organic substance

Derivatives of an organic substance containing one or more groups selected from the group consisting of sulfanyl, selanyl and sulfino may be produced by reacting an organic substance containing one or more groups selected from the group consisting of sulfanyl, selanyl and sulfino with an olefin compound containing an ethylene structure having at least two electron-withdrawing groups except halogen atoms under an acidic condition to form a derivative of the organic substance