The present teachings disclose contacting an amine salt catalyst with a dicarbonyl compound having an alkylene group between the carbonyl group; adding formaldehyde, paraformaldehyde, or formalin in an amount of about 2:1 to about 3:1 moles of formaldehyde to moles of the dicarbonyl compound to form a mixture; and refluxing the mixture. The process forms a carbonyl-substituted alkene. The process may be performed in the absence of a solvent. The process may form methylene malonates, methylene dimalonates, methylene keto malonamides, methylene diketones, methylene keto esters, and the like.

Polymerization inhibitor compositions are provided. The polymerization inhibitor compositions may include at least one hydroxylamine of a nitroxide and at least one phenylenediamine. Methods of inhibiting the unwanted polymerization of monomers are also provided. The methods include adding the presently disclosed polymerization inhibitor compositions to a fluid containing the monomers. The monomers may be ethylenically unsaturated monomers, such as acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, acrolein, methacrolein, acrylate, methacrylate, acrylamide, methacrylamide, vinyl acetate, butadiene, ethylene, propylene, and styrene.

Polymerization inhibitor compositions are provided. The polymerization inhibitor compositions may include at least one hydroxylamine of a nitroxide and at least one phenylenediamine. Methods of inhibiting the unwanted polymerization of monomers are also provided. The methods include adding the presently disclosed polymerization inhibitor compositions to a fluid containing the monomers. The monomers may be ethylenically unsaturated monomers, such as acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, acrolein, methacrolein, acrylate, methacrylate, acrylamide, methacrylamide, vinyl acetate, butadiene, ethylene, propylene, and styrene.

The invention relates to an integrated process for the production of ethylene and vinyl acetate (VAM), comprising contacting in a first reaction zone a gas stream comprising ethane and optionally ethylene with an oxygen-containing gas stream in the presence of a oxydehydrogenation catalyst under oxidative dehydrogenation conditions to produce a first product stream comprising ethane, ethylene, acetic acid and water, and optionally other compounds, separating said first product stream in a vapor permeation unit into a second stream comprising water and a third stream comprising ethane, ethylene, acetic acid, and optionally other gaseous compounds, contacting in a second reaction zone all or at least a portion of said third stream with a stream comprising concentrated acetic acid and with an oxygen-containing gas stream in the presence of a VAM catalyst, to produce a fourth product stream comprising vinyl acetate, acetic acid, ethane, ethylene, water, carbon dioxide, and optionally other compounds, separating said fourth product stream in a vinyl acetate separation zone into a fifth stream comprising vinylacetate, acetic acid, water and optionally other condensable compounds, and a sixth stream comprising ethylene, ethane, carbon dioxide and optionally other gaseous compounds, and recovering vinyl acetate from said fifth stream. The invention further relates to a reaction system for carrying out the process.

The invention relates to an integrated process for the production of ethylene and vinyl acetate (VAM), comprising contacting in a first reaction zone a gas stream comprising ethane and optionally ethylene with an oxygen-containing gas stream in the presence of a oxydehydrogenation catalyst under oxidative dehydrogenation conditions to produce a first product stream comprising ethane, ethylene, acetic acid and water, and optionally other compounds, separating said first product stream in a vapor permeation unit into a second stream comprising water and a third stream comprising ethane, ethylene, acetic acid, and optionally other gaseous compounds, contacting in a second reaction zone all or at least a portion of said third stream with a stream comprising concentrated acetic acid and with an oxygen-containing gas stream in the presence of a VAM catalyst, to produce a fourth product stream comprising vinyl acetate, acetic acid, ethane, ethylene, water, carbon dioxide, and optionally other compounds, separating said fourth product stream in a vinyl acetate separation zone into a fifth stream comprising vinylacetate, acetic acid, water and optionally other condensable compounds, and a sixth stream comprising ethylene, ethane, carbon dioxide and optionally other gaseous compounds, and recovering vinyl acetate from said fifth stream. The invention further relates to a reaction system for carrying out the process.

Process for purification of unreacted vinyl acetate monomers comprising the steps of preliminarily loading an adsorbent agent bed with a mixture comprising an inert gas and fresh vinyl acetate; and feeding said adsorbent agent bed with unreacted vinyl acetate monomers to remove acetic acid.

Process for purification of unreacted vinyl acetate monomers comprising the steps of preliminarily loading an adsorbent agent bed with a mixture comprising an inert gas and fresh vinyl acetate; and feeding said adsorbent agent bed with unreacted vinyl acetate monomers to remove acetic acid.

A catalyst includes a support, where the support includes an external surface, about 60 wt % to about 99 wt % silica, and about 1.0 wt % to about 5.0 wt % alumina. A catalytic layer is disposed within the support adjacent to the external surface, where the catalytic layer further includes Pd, Au, and potassium acetate (KOAc). In the catalyst, (a) the KOAc is from about 60 kg/m.sup.3 to about 150 kg/m.sup.3 of the catalyst; or (b) the catalytic layer has an average thickness from about 50 m to about 150 m; or (c) both (a) and (b). The catalyst also possesses a Brunauer-Emmett-Teller surface area of about 130 m.sup.2/g to about 300 m.sup.2/g and a geometric surface area per packed bed volume from about 550 m.sup.2/m.sup.3 to about 1500 m.sup.2/m.sup.3. The catalyst is highly active for the synthesis of vinyl acetate monomer and exhibits a high selectivity for vinyl acetate monomer.

A catalyst includes a support, where the support includes an external surface, about 60 wt % to about 99 wt % silica, and about 1.0 wt % to about 5.0 wt % alumina. A catalytic layer is disposed within the support adjacent to the external surface, where the catalytic layer further includes Pd, Au, and potassium acetate (KOAc). In the catalyst, (a) the KOAc is from about 60 kg/m.sup.3 to about 150 kg/m.sup.3 of the catalyst; or (b) the catalytic layer has an average thickness from about 50 m to about 150 m; or (c) both (a) and (b). The catalyst also possesses a Brunauer-Emmett-Teller surface area of about 130 m.sup.2/g to about 300 m.sup.2/g and a geometric surface area per packed bed volume from about 550 m.sup.2/m.sup.3 to about 1500 m.sup.2/m.sup.3. The catalyst is highly active for the synthesis of vinyl acetate monomer and exhibits a high selectivity for vinyl acetate monomer.

The present invention provides a technique capable of adjusting the loading positions of gold and palladium in a VAM catalyst by a method of producing a palladium-gold loaded catalyst for vinyl acetate synthesis. The method includes a step of impregnating a spherical porous molded carrier of an inorganic oxide with a mixed aqueous solution containing a palladium precursor as a catalytically active species and a gold precursor as a co-catalyst component, and subsequently impregnating the resultant spherical porous molded carrier with an aqueous alkaline solution to water-insolubilize the palladium precursor and the gold precursor in the spherical porous molded carrier to obtain a palladium-gold immobilized spherical porous molded carrier; and a subsequent step of adjusting the moisture content of the palladium-gold immobilized spherical porous molded carrier.