A novel process can be used for purifying methyl methacrylate (MMA) contaminated with low-boiling components by distillation, where the process involves producing MMA by oxidative esterification, and a crude product containing methyl propionate (MP), methyl isobutyrate (MIB), and methacrolein (MAL) as low-boiling components. The process is compatible with MMA produced from C.sub.2-based methacrolein containing the low-boiling components specified.

A novel process can be used for purifying methyl methacrylate (MMA) contaminated with low-boiling components by distillation, where the process involves producing MMA by oxidative esterification, and a crude product containing methyl propionate (MP), methyl isobutyrate (MIB), and methacrolein (MAL) as low-boiling components. The process is compatible with MMA produced from C.sub.2-based methacrolein containing the low-boiling components specified.

A process can be used for producing methacrylic acid or a methacrylic acid ester. The process involves producing acrolein, reacting the produced acrolein with hydrogen to produce propanal, reacting the propanal with formaldehyde to produce methacrolein, and oxidizing the methacrolein in the presence of an oxygen containing gas and optionally an alcohol, to obtain methacrylic acid or methacrylic acid ester.

A process can be used for producing methacrylic acid or a methacrylic acid ester. The process involves producing acrolein, reacting the produced acrolein with hydrogen to produce propanal, reacting the propanal with formaldehyde to produce methacrolein, and oxidizing the methacrolein in the presence of an oxygen containing gas and optionally an alcohol, to obtain methacrylic acid or methacrylic acid ester.

A process can be used for producing methacrylic acid or a methacrylic acid ester. The process involves producing acrolein, reacting the produced acrolein with hydrogen to produce propanal, reacting the propanal with formaldehyde to produce methacrolein, and oxidizing the methacrolein in the presence of an oxygen containing gas and optionally an alcohol, to obtain methacrylic acid or methacrylic acid ester.

A series of new macrocycles and cage-like molecules are obtained in a high yield from a bis-(2,4-dialkoxyphenyl)arene (naphthalene, anthracene, pyrene, porphyrin, etc.) or a tris-(2,4-dialkoxyphenyl)arene (benzene, sym-tribenzobenzene) and paraformaldehyde under the catalysis of a Lewis acid. In addition, perhydroxybiphenylarenes (tetrabiphenyl trimer, naphthalene dimer, etc.) can be obtained by means of demethylation, and a variety of water-soluble derivatives can be obtained by further modification, with same exhibiting a good bond ability for guest molecules (purpurine, etc.). Moreover, the functional group introduced into the backbone enables the macrocycle to have excellent adsorption and separation capabilities and a photophysical property. The macrocyclic and cage-like molecules have commercially available raw materials, are simple to synthesize, have a high yield, and are convenient to modify, such that same have wide application prospects in gas adsorption and separation, facilitate performance improvement of luminescent materials, perform adsorption of water-soluble toxic substances, etc.

The present teachings are directed at 1,1-disubstituted alkene monomers (e.g., methylene beta-ketoester monomers), methods for producing the same, polymerizable compositions including a methylene beta-ketoester monomer, and polymers, compositions and products formed therefrom. The monomer preferably is a high purity monomer. In the method for producing the methylene beta-ketoesters of the invention, a beta-ketoester may be reacted with a source of formaldehyde. The methylene beta-ketoester monomers may be used in monomer-based products (e.g., inks, adhesives, coatings, sealants or reactive molding) and polymer-based products (e.g., fibers, films, sheets, medical polymers, composite polymers and surfactants).

The present teachings are directed at 1,1-disubstituted alkene monomers (e.g., methylene beta-ketoester monomers), methods for producing the same, polymerizable compositions including a methylene beta-ketoester monomer, and polymers, compositions and products formed therefrom. The monomer preferably is a high purity monomer. In the method for producing the methylene beta-ketoesters of the invention, a beta-ketoester may be reacted with a source of formaldehyde. The methylene beta-ketoester monomers may be used in monomer-based products (e.g., inks, adhesives, coatings, sealants or reactive molding) and polymer-based products (e.g., fibers, films, sheets, medical polymers, composite polymers and surfactants).

A process and a preparation plant prepares methacrolein from formaldehyde and propionaldehyde, in presence of water and a homogeneous catalyst based at least on an acid and a base. A reaction mixture is introduced into a methacrolein workup plant and separated in a first distillation column, into a first distillation mixture in a gas phase at the top and a second distillation mixture in a liquid phase at the bottom. The first distillation mixture is condensed and, in a first phase separator, the organic phase and the aqueous phase of the condensate are separated from one another. The aqueous phase is introduced into a second distillation column, that is not part of the methacrolein workup plant, and is separated into a third distillation mixture in a gas phase at the top and a fourth distillation mixture at the bottom. The third distillation mixture is introduced into the methacrolein workup plant.

A process and a preparation plant prepares methacrolein from formaldehyde and propionaldehyde, in presence of water and a homogeneous catalyst based at least on an acid and a base. A reaction mixture is introduced into a methacrolein workup plant and separated in a first distillation column, into a first distillation mixture in a gas phase at the top and a second distillation mixture in a liquid phase at the bottom. The first distillation mixture is condensed and, in a first phase separator, the organic phase and the aqueous phase of the condensate are separated from one another. The aqueous phase is introduced into a second distillation column, that is not part of the methacrolein workup plant, and is separated into a third distillation mixture in a gas phase at the top and a fourth distillation mixture at the bottom. The third distillation mixture is introduced into the methacrolein workup plant.