Abstract: A process for preparing essentially pure 3-chlorophthalic anhydride from a mixture in which 3-chlorophthalic anhydride is present in addition to 4,5-dichlorophthalic anhydride, which involves first distilling off a mixture of 3-chlorophthalic anhydride and 4,5-dichlorophthalic anhydride, so that the obtained bottoms is essentially free of 4,5-dichlorophthalic anhydride, and then by distillation of the obtained bottoms, recovering 3-chlorophthalic anhydride in a second distillation step. The starting mixture is preferably prepared without solvent in a melt by incomplete chlorination of phthalic anhydride using FeCl.sub.3 as a catalyst.

Abstract: A reel for strip-like recording substrates, in particular photographic films, with a slot provided in the reel core and at least one hook provided therein for fixing the end of the tape inserted into the slot, wherein the upper and lower side of the hook are joined together by an oblique face at the end opposite the film insertion side, in such a manner that the hook tapers towards the hook end and the hook surface is longer than the hook under-side, and wherein any chosen sections parallel to the under-side of the hook through the oblique face produce arcuate lines of intersection, ensuring secure insertion of the film end.

Abstract: The invention relates to a process for removing water traces from a liquid phosgene stream in chemical processes which employ a phosgenation step. Water traces are removed from a liquid phosgene stream containing at least 60 weight percent phosgene by contacting the stream with a strongly basic macroreticular anion exchange resin which catalyzes the reaction between phosgene and the water traces.

Abstract: A process for recovering caprolactam from oligomers and/or polymers of caprolactam comprises the following steps:a) treating oligomers and/or polymers of caprolactam with from 1 to 20 parts by weight of water per part by weight of oligomer or polymer at from 200.degree. to 350.degree. C. under superatmospheric pressure with a residence time of from 0.5 to 10 hours to form an aqueous reaction mixture comprising polycaprolactam, monomeric caprolactam and oligomers thereof, andb) passing the aqueous reaction mixture obtained in a) into a fluidized bed of alumina at from 250.degree. to 400.degree. C. to obtain a mixture of steam and caprolactam.

Abstract: Trialkylamines and methyl formate are recovered from reaction mixtures obtained in the preparation of trimethylolalkanes by reaction of n-alkanals with from 2.2 to 4.5 moles of formaldehyde in aqueous solution in the presence of from 0.6 to 3 mole of trialkylamine, each quantity based on 1 mole of alkanal, and subsequent hydrogenation in a process wherein the crude reaction mixturea) is heated to from 100.degree. to 200.degree. C.

Abstract: A method of separating .gamma.-butyrolactone from a mixture containing ethanol, tetrahydrofuran, water, n-butanol, 1,4-butanediol, diethyl succinate and .gamma.-butyrolactone, by distillation in vacuum columns.

Abstract: A process for the preparation of nicotinamide by amidation of a nicotinic acid/nicotinamide melt, vacuum distillation of the amidation mixture, removal of the nicotinamide as the bottom product and recycling of the top product, depleted with respect to nicotinamide, into the amidation stage together with addition of fresh amounts of nicotinic acid.

Abstract: A process for conjointly preparing methyl tert.-butyl ether and obtaining isobutene from an isobutene-containing C.sub.4 -hydrocarbon mixture. In the process the C.sub.4 -hydrocarbon mixture is reacted, in one or more etherification stages, with methanol and a primary C.sub.3 - or C.sub.4 -alcohol in the presence of an acid condensing agent, the resulting reaction mixture or mixtures are then separated into a fraction containing the unconverted hydrocarbons, the methyl tert.-butyl ether and a fraction containing the C.sub.3 - or C.sub.4 -alkyl tert.-butyl ether. Thereafter, the C.sub.3 - or C.sub.4 -alkyl tert.-butyl ether is decomposed at an elevated temperature, in the presence of an acid catalyst, into isobutene and primary C.sub.3 - or C.sub.4 -alcohol.

Abstract: A process for obtaining isobutene from a C.sub.4 -hydrocarbon mixture containing isobutene, by reacting the mixture with a primary alcohol in the presence of an acid condensing agent and decomposing the resulting tertiary ether in the presence of an acid catalyst at an elevated temperature, wherein a primary C.sub.3 - or C.sub.4 -alcohol is used.