Abstract: A process is described for continuously preparing alkyl esters of (meth)acrylic acid by reacting (meth)acrylic acid and alkanols having from 1 to 5 carbon atoms in homogeneous, liquid, solvent-free phase at elevated temperature and in the presence of an acidic esterification catalyst, in which the (meth)acrylic acid, the alkanol and the acidic esterification catalyst are fed to a reaction zone (5, 6), a reaction mixture (21) is discharged from the reaction zone (5, 6), and is introduced into a rectification unit I and separated by addition of water into a top stream (23), comprising the alkyl ester of (meth)acrylic acid, and a bottom stream (22), and a substream of the bottom stream (22) from the rectification unit I is fed to a residue dissociation unit IV, which comprises a dissociating boiler (61), and is separated therein into a top stream (29), which is recycled into the rectification unit I and a bottom stream (40), which is removed from the system, wherein the residue dissociation unit IV, as wel

Abstract: A continuously operated heterogeneously catalyzed gas-phase partial oxidation of at least one organic compound in an oxidation reactor is operated safely by a process in which an explosion diagram for the feed gas mixture is deposited as the basis of a cut-out mechanism in a computer.

Abstract: Higher (meth)acrylates IV are prepared by transesterification of a lower (meth)acrylate I with a higher alcohol R2OH in the presence of a stabilizer or stabilizer mixture and of a catalyst or catalyst mixture, by a process in which the liberated lower alkanol R1OH is separated off and is fed at least partly to the preparation of the lower (meth)acrylate I.

Abstract: Higher (meth)acrylates IV are prepared by transesterification of a lower (meth)acrylate I with a higher alcohol R2OH in the presence of a stabilizer or stabilizer mixture and of a catalyst or catalyst mixture, by a process in which the liberated lower alkanol R1OH is separated off and is fed at least partly to the preparation of the lower (meth)acrylate I.

Abstract: A continuously operated heterogeneously catalyzed gas-phase partial oxidation of at least one organic compound in an oxidation reactor is operated safely by a process in which an explosion diagram for the feed gas mixture is deposited as the basis of a cut-out mechanism in a computer.

Abstract: A method for measuring the temperature of fluid masses being treated in a tubular reactor apparatus which comprises carrying out the treatment in reactor apparatus comprises at least two same-type tubular reactors which are filled with solid particles, at least one tubular reactor containing a temperature measuring unit, the tubular reactors being designed such that both the ratio of the mass of the solid particles to the free cross-sectional area of the respective tubular reactor and the pressure drop measured by an inert gas being conducted transversely to the free cross-sectional area are each substantially identical across the respective tubular reactor. The apparatus is suitable for treating fluid masses while generating or consuming thermal energy, the temperature being measured.

Abstract: A reactor apparatus comprises at least two same-type tubular reactors which are filled with solid particles, at least one tubular reactor containing a temperature measuring unit, the tubular reactors being designed such that both the ratio of the mass of the solid particles to the free cross-sectional area of the respective tubular reactor and the pressure drop measured by an inert gas being conducted transversely to the free cross-sectional area are identical across the respective tubular reactor. The apparatus is suitable for treating fluid masses while generating or consuming thermal energy, the temperature being measured.

Abstract: In a process for the disposal of low, mediun, and high-boiling secondary components formed during the preparation of (meth)acrylic acid the gaseous low-boiling secondary components are burned, whilst low-boiling and medium-boiling secondary components that are dissolved in water optionally together with high-boiling secondary components treated with solvent are added.

Abstract: A reactor apparatus comprises at least two same-type tubular reactors which are filled with solid particles, at least one tubular reactor containing a temperature measuring unit, the tubular reactors being designed such that both the ratio of the mass of the solid particles to the free cross-sectional area of the respective tubular reactor and the pressure drop measured by an inert gas being conducted transversely to the free cross-sectional area are identical across the respective tubular reactor. The apparatus is suitable for treating fluid masses while generating or consuming thermal energy, the temperature being measured.

Abstract: A process for the preparation of C.sub.1 -C.sub.4 -alkyl esters of (meth)acrylic acid from esters of the formula I ##STR1## and in case from esters of the formula (II) ##STR2## where R.sup.1 is hydrogen or --CH.sub.3,R.sup.2 and R.sup.3 are each C.sub.1 -C.sub.4 -alkyl, andn is an integer >0,in the liquid phase and in the presence of an acid at reduced pressure and with continuous removal of the cleavage products.

Abstract: In a process for the separation by rectification of unsaturated carboxylic acids from solvents in which the acids were absorbed after the synthesis reaction, the rectification is briefly interrupted and the rectification column is flushed with a basic solution. The interruption is carried out at regular time intervals. The basic solution used is an aqueous solution of alkali metal and/or alkaline earth metal hydroxide, preferably NaOH, KOH, Ca(OH).sub.2 or their anhydrous oxides; alkaline polar organic solvents as amines or amides can be used, too.

Abstract: A diester of (meth)acrylic acid with a C.sub.4 -C.sub.6 -alkanediol is separated from a mixture which essentially consists of the C.sub.4 -C.sub.6 -alkanediol, the monoester of (meth)acrylic acid with the C.sub.4 -C.sub.6 -alkanediol and the diester of (meth)acrylic acid with the C.sub.4 -C.sub.6 -alkanediol by extraction with an organic solvent in the presence of water, by a process in which the diester-containing mixture is added continuously in the middle section of an extraction column and in addition water and the organic extracting agent are passed continuously countercurrent in the extraction column.

Abstract: A process for the separation of a mono(meth)acrylate of a C.sub.4 -C.sub.6 alkanediol from an aqueous solution containing a mono(meth)acrylate of a C.sub.4 -C.sub.6 alkanediol and the said C.sub.4 -C.sub.6 alkanediol, by extraction with an organic solvent, in which the extracting agent used is an organic solvent selected from the group comprising esters of C.sub.1 -C.sub.4 alkanecarboxylic acids and C.sub.1 -C.sub.5 alkanols, single and mixed dialkyl ethers having from 4 to 8 C atoms, and mixtures of such organic solvents.