The invention relates to a process for preparation of at least one of methacrylic acid and a methacrylic acid ester, comprising the process stepsgas phase oxidation of at least one C.sub.4 compound, quenching of the reaction phase, separation and purification of the obtained methacrylic acid and optionally esterification, wherein the C.sub.4 compound is a methacrolein comprising mixture, originating from at least two different methacrolein sources, a first methacrolein source being a feed stream obtained by the heterogeneously catalyzed gas phase oxidation of isobutylene or tert-butyl alcohol or isobutylaldehyde or a mixture of two or more thereof, a second methacrolein source being a feed stream obtained by the reaction of propionaldehyde with a C.sub.1 extending agent, preferably formaldehyde, and where said methacrolein can be obtained either completely from the first methacrolein source, or completely from the second methacrolein source or from any mixture of both.

The invention relates to a process for preparation of at least one of methacrylic acid and a methacrylic acid ester, comprising the process stepsgas phase oxidation of at least one C.sub.4 compound, quenching of the reaction phase, separation and purification of the obtained methacrylic acid and optionally esterification, wherein the C.sub.4 compound is a methacrolein comprising mixture, originating from at least two different methacrolein sources, a first methacrolein source being a feed stream obtained by the heterogeneously catalyzed gas phase oxidation of isobutylene or tert-butyl alcohol or isobutylaldehyde or a mixture of two or more thereof, a second methacrolein source being a feed stream obtained by the reaction of propionaldehyde with a C.sub.1 extending agent, preferably formaldehyde, and where said methacrolein can be obtained either completely from the first methacrolein source, or completely from the second methacrolein source or from any mixture of both.

A commercially available anatase titania catalyst is shown to be catalytically active towards the formation of methacrolein from formaldehyde and propionaldehyde with conversions and selectivities close to 90%. This titania catalyst is readily available, non-toxic, and can be used with formaldehyde and a variety of other aldehyde compounds to make α,β-unsaturated aldehyde compounds. This process benefits from low raw material costs and is economically advantaged due to the elimination of catalyst separation. An additional advantage of this method involves the ability of the catalyst to be fully regenerated after a calcination step at 450° C. in air. This process shows promising stability and selectivity during lifetime studies, particularly when performed in the presence of a hydrogen carrier gas.

A commercially available anatase titania catalyst is shown to be catalytically active towards the formation of methacrolein from formaldehyde and propionaldehyde with conversions and selectivities close to 90%. This titania catalyst is readily available, non-toxic, and can be used with formaldehyde and a variety of other aldehyde compounds to make α,β-unsaturated aldehyde compounds. This process benefits from low raw material costs and is economically advantaged due to the elimination of catalyst separation. An additional advantage of this method involves the ability of the catalyst to be fully regenerated after a calcination step at 450° C. in air. This process shows promising stability and selectivity during lifetime studies, particularly when performed in the presence of a hydrogen carrier gas.

A commercially available anatase titania catalyst is shown to be catalytically active towards the formation of methacrolein from formaldehyde and propionaldehyde with conversions and selectivities close to 90%. This titania catalyst is readily available, non-toxic, and can be used with formaldehyde and a variety of other aldehyde compounds to make α,β-unsaturated aldehyde compounds. This process benefits from low raw material costs and is economically advantaged due to the elimination of catalyst separation. An additional advantage of this method involves the ability of the catalyst to be fully regenerated after a calcination step at 450° C. in air. This process shows promising stability and selectivity during lifetime studies, particularly when performed in the presence of a hydrogen carrier gas.

A process is described that uses a silver catalyst to convert methanol into formaldehyde in the presence of less than a stoichiometric amount of oxygen. The resulting formaldehyde is reacted without isolation with propionaldehyde over a commercially available anatase titania catalyst that is shown to be catalytically active towards the formation of methacrolein from formaldehyde and propionaldehyde with conversions and selectivities close to 90%. This titania catalyst is readily available, non-toxic, and can be used with formaldehyde and a variety of other aldehyde compounds to make α,β-unsaturated aldehyde compounds. This process benefits from low raw material costs and is economically advantaged due to the elimination of catalyst separation. This process shows promising stability and selectivity during lifetime studies, particularly when performed in the presence of a hydrogen carrier gas.

A process is described that uses a silver catalyst to convert methanol into formaldehyde in the presence of less than a stoichiometric amount of oxygen. The resulting formaldehyde is reacted without isolation with propionaldehyde over a commercially available anatase titania catalyst that is shown to be catalytically active towards the formation of methacrolein from formaldehyde and propionaldehyde with conversions and selectivities close to 90%. This titania catalyst is readily available, non-toxic, and can be used with formaldehyde and a variety of other aldehyde compounds to make α,β-unsaturated aldehyde compounds. This process benefits from low raw material costs and is economically advantaged due to the elimination of catalyst separation. This process shows promising stability and selectivity during lifetime studies, particularly when performed in the presence of a hydrogen carrier gas.

A process is described that uses a silver catalyst to convert methanol into formaldehyde in the presence of less than a stoichiometric amount of oxygen. The resulting formaldehyde is reacted without isolation with propionaldehyde over a commercially available anatase titania catalyst that is shown to be catalytically active towards the formation of methacrolein from formaldehyde and propionaldehyde with conversions and selectivities close to 90%. This titania catalyst is readily available, non-toxic, and can be used with formaldehyde and a variety of other aldehyde compounds to make α,β-unsaturated aldehyde compounds. This process benefits from low raw material costs and is economically advantaged due to the elimination of catalyst separation. This process shows promising stability and selectivity during lifetime studies, particularly when performed in the presence of a hydrogen carrier gas.

The present invention relates to the oxidative combustion of amine-containing wastewaters, especially in a process for preparing methacrolein. Methacrolein is used in chemical synthesis particularly as an intermediate for preparation of methacrylic acid, methyl methacrylate, or else of active ingredients, odorants or flavorings. More particularly, the present invention relates to an oxidative combustion of the amine-containing wastewaters with only low nitrogen oxide formation.

The present invention relates to the oxidative combustion of amine-containing wastewaters, especially in a process for preparing methacrolein. Methacrolein is used in chemical synthesis particularly as an intermediate for preparation of methacrylic acid, methyl methacrylate, or else of active ingredients, odorants or flavorings. More particularly, the present invention relates to an oxidative combustion of the amine-containing wastewaters with only low nitrogen oxide formation.