There is provided a catalyst having an average electronegativity of 2.1 or more and 2.8 or less.

The invention relates to a composition for the immediate termination of a free-radical polymerization, the use thereof for the stabilization of free-radically polymerizable monomers against free-radical polymerization and a method for the immediate termination of free-radical polymerizations.

The invention relates to a composition for the immediate termination of a free-radical polymerization, the use thereof for the stabilization of free-radically polymerizable monomers against free-radical polymerization and a method for the immediate termination of free-radical polymerizations.

There is provided a catalyst that enables the production of isobutylene with a high selectivity in the production of isobutylene by dehydration of isobutanol. The catalyst according to the present invention contains at least one metal selected from Group 6 to Group 14 metal elements in Period 4 to Period 6 of the periodic table, in alumina which includes alumina consisting of one or more crystal phases of a monoclinic crystal phase, a tetragonal crystal phase, and a cubic crystal phase.

There is provided a catalyst that enables the production of isobutylene with a high selectivity in the production of isobutylene by dehydration of isobutanol. The catalyst according to the present invention contains at least one metal selected from Group 6 to Group 14 metal elements in Period 4 to Period 6 of the periodic table, in alumina which includes alumina consisting of one or more crystal phases of a monoclinic crystal phase, a tetragonal crystal phase, and a cubic crystal phase.

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.

An object of the present invention is to provide a catalyst capable of improving the selectivity of unsaturated aldehydes and unsaturated carboxylic acids, and a catalyst containing molybdenum, antimony, bismuth, and iron, wherein an atom ratio of the antimony to the molybdenum on a surface of the catalyst is greater than an atom ratio of the antimony to the molybdenum in the entire catalyst is provided.

An object of the present invention is to provide a catalyst capable of improving the selectivity of unsaturated aldehydes and unsaturated carboxylic acids, and a catalyst containing molybdenum, antimony, bismuth, and iron, wherein an atom ratio of the antimony to the molybdenum on a surface of the catalyst is greater than an atom ratio of the antimony to the molybdenum in the entire catalyst is provided.

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.