Abstract: The invention relates to a process for the production of (meth)acrylic acid esters of polyhydric alcohols by reaction of the reactants with acrylic acid and/or methacrylic acid in the presence of acidic esterification catalysts with addition of sterically hindered phenolic compounds as polymerization inhibitors. The process is characterized in that tocopherols are used as the sterically hindered phenolic compounds and .alpha.-tocopherol is preferably at least partly used. The process is preferably carried out using reaction mixtures which are liquid at room temperature and which are at least substantially free from solvents and/or azeotropic entraining agents; more particularly, the water of condensation formed is removed from the gas phase of the reaction zone.

Abstract: The invention relates to a process for the production of (meth)acrylic acid esters of polyhydric alcohols by reaction of the reactants in the presence of acidic esterification catalysts with addition of .alpha.-substituted phenolic compounds, more particularly di-tert.-butyl hydroquinone, as polymerization inhibitors. The new process is characterized in that the reaction mixtures used are liquid at room temperature and are at least substantially free from solvents and/or azeotropic entraining agents and in that the water of condensation formed is removed from the gas phase of the reaction zone.

Abstract: The invention relates to a process for the production of pure, substantially neutral, low-volatility organic compounds containing reactive olefinic double bonds from starting materials which contain these components together with small quantities of acidic reaction constituents and/or corresponding auxiliaries in the liquid phase by neutralization and separation of the salts formed. The process according to the invention is characterized in that, to obtain pure products which combine low residual acid values with low color standard numbers, even without distillation, the neutralization is carried out as dry neutralization using solid, finely powdered oxides, carbonates and/or hydroxides of the alkali and/or alkaline earth metals, if desired together with other insoluble basic metal oxide compounds, and the organic liquid phase is subsequently separated from the finely powdered solid phase. The oxides and/or hydroxides of calcium and/or magnesium are preferably used for neutralization.

Abstract: The invention relates to a process for the production of (meth)acrylic acid esters of polyhydric alcohols by reaction thereof with acrylic acid and/or methacrylic acid in the presence of acidic esterification catalysts with addition of polymerization inhibitors to the reaction mixture. The new process is characterized in that, where unsubstituted phenolic compounds are used as inhibitors, the esterification reaction is carried out with addition of active carbon to the reaction mixture. The preferred inhibitor is hydroquinone. In addition, the esterification reaction is preferably carried out in the absence of liquid solvents and/or azeotropic entraining agents.

Abstract: A process for the production of (meth)acrylic acid esters of polyhydric alcohols by reaction of the reactants in the presence of acidic esterification catalysts with addition of polymerization inhibitors to the reaction mixture and purging of the reactor interior with an oxygen-containing gas stream. The process is characterized in that that part of the reactor interior filled with gas phase is charged with finely divided liquid droplets containing polymerization inhibitor.

Abstract: A droplet separator for removing drops of liquid from a gas stream comprises a stack of corrugated plates each of which is generally planar but has a plurality of corrugations formed by alternating crests and troughs of given wavelength and amplitude. The troughs of adjacent plates register with one another to define flow passages for the gas stream extending generally in a flow direction between the inlet and outlet sides of the stack. The crests of adjacent plates contact one another between the flow passages and each of the flow passages is formed with at least two bends in the plate plane effecting direction change in the gas flowing therethrough. The corrugations are all of trapezoidal cross section.

Abstract: An apparatus for the separation of liquid droplets or fine-particulate solids from a gas stream entraining same in which a plurality of geometrically identical separator plates define flow passages between them for the gas. The plates are formed with corrugations and the crests or troughs of the corrugations are provided with phase-separating chambers open in the direction of the oncoming gas stream. The gas stream entering the gaps at the inlet sides of the phase-separating chambers precipitates the liquid or solids which are conducted downwardly along chambers formed by the phase-separating chambers which are oriented vertically. According to the invention, the successive corrugations (i.e. successive crests or troughs) of each separator plate in the direction of flow are provided with decreasing heights (measured perpendicularly to a median plane through the plate) and the successive corrugations are of decreasing width in the direction of flow of the gas.