Described herein are compounds of formula (I) as properfume compounds. In particular, described herein is a method to release a compound being a ketone of formula (II), a formate ester of formula (III), and/or an alcohol of formula (IV) by exposing the compound of formula (I) to an environment wherein it is oxidized. Moreover, a perfuming composition and a perfumed consumer product including at least one compound of formula (I) are also described.

A catalyst comprising a noble metal disposed on a support. The noble metal is present in an amount ranging from 0.1 wt % to 10 wt % relative to the total weight of the catalyst. The support comprises at least 50 wt % silicon carbide relative to the total weight of the support. The silicon carbide has a surface area of at least 5 m.sup.2/g. A method for preparing methyl methacrylate from methacrolein and methanol using the catalyst is also disclosed.

A catalyst comprising a noble metal disposed on a support. The noble metal is present in an amount ranging from 0.1 wt % to 10 wt % relative to the total weight of the catalyst. The support comprises at least 50 wt % silicon carbide relative to the total weight of the support. The silicon carbide has a surface area of at least 5 m.sup.2/g. A method for preparing methyl methacrylate from methacrolein and methanol using the catalyst is also disclosed.

A catalyst for production of carboxylic acid ester, containing: catalyst particles containing at least one element selected from the group consisting of nickel, cobalt, palladium, lead, platinum, ruthenium, gold, silver, and copper; and a support supporting the catalyst particles, wherein the catalyst for production of carboxylic acid ester has half-width Wa of pore distribution of 10 nm or less, the half-width Wa being calculated using BJH method from an adsorption isotherm obtained by nitrogen adsorption.

A catalyst for production of carboxylic acid ester, containing: catalyst particles containing at least one element selected from the group consisting of nickel, cobalt, palladium, lead, platinum, ruthenium, gold, silver, and copper; and a support supporting the catalyst particles, wherein the catalyst for production of carboxylic acid ester has half-width Wa of pore distribution of 10 nm or less, the half-width Wa being calculated using BJH method from an adsorption isotherm obtained by nitrogen adsorption.

A process for producing alkyl methacrylates, in particular methyl methacrylate (MMA), includes production of methacrolein (MAL) in a first reaction stage; direct oxidative esterification (DOE) of the methacrolein with an alcohol, preferably methanol, to afford an alkyl methacrylate in a second reaction stage; and workup of the alkyl methacrylate crude product from the second reaction stage. An optimized workup of the reactor output from the oxidative esterification of methacrolein involves minimizing the amount of employed water, the amount of employed acid, and/or the amount of aqueous waste streams, through an optimized recycling of the generated process water streams.

A process for producing alkyl methacrylates, in particular methyl methacrylate (MMA), includes production of methacrolein (MAL) in a first reaction stage; direct oxidative esterification (DOE) of the methacrolein with an alcohol, preferably methanol, to afford an alkyl methacrylate in a second reaction stage; and workup of the alkyl methacrylate crude product from the second reaction stage. An optimized workup of the reactor output from the oxidative esterification of methacrolein involves minimizing the amount of employed water, the amount of employed acid, and/or the amount of aqueous waste streams, through an optimized recycling of the generated process water streams.

A process for producing alkyl methacrylates, in particular methyl methacrylate (MMA), includes production of methacrolein (MAL) in a first reaction stage; direct oxidative esterification (DOE) of the methacrolein with an alcohol, preferably methanol, to afford an alkyl methacrylate in a second reaction stage; and workup of the alkyl methacrylate crude product from the second reaction stage. An optimized workup of the reactor output from the oxidative esterification of methacrolein involves minimizing the amount of employed water, the amount of employed acid, and/or the amount of aqueous waste streams, through an optimized recycling of the generated process water streams.

A heterogeneous catalyst comprising a support and gold, wherein: (i) said support comprises alumina, (ii) said catalyst comprises from 0.1 to 5 wt % of gold, (iii) at least 90 wt % of the gold is in the outer 60% of catalyst volume, and (iv) particles of the catalyst have an average diameter from 200 microns to 30 mm; wherein weight percentages are based on weight of the catalyst.

A heterogeneous catalyst comprising a support and gold, wherein: (i) said support comprises alumina, (ii) said catalyst comprises from 0.1 to 5 wt % of gold, (iii) at least 90 wt % of the gold is in the outer 60% of catalyst volume, and (iv) particles of the catalyst have an average diameter from 200 microns to 30 mm; wherein weight percentages are based on weight of the catalyst.