Abstract: A quantitative enrichment of volatile compounds from substances of the macro- to submicro field in a short time is realized by capillary distillation in a system which includes an evaporator vessel, on the bottom of which one or more filter plates are provided and which is connected to a condensing vessel by means of a capillary tube. The presence of filter plate(s) guarantees a uniform and constant boiling which facilitates the quantitative isolation of the volatile compounds.

Abstract: Alkylisothiocyanic acid esters having the formula R--N.dbd.C.dbd.S can be prepared by reacting N-alkyldithiocarbamates with hydrogen peroxide in aqueous phase at 95.degree. to 130.degree. C. The aqueous solution of N-alkyldithiocarbamate is reacted with a 20 to 40% by weight aqueous solution of hydrogen peroxide in a volumetric ratio of 1 to 0.8 to 1 while maintaining a pH of 1.5 to 4.5. The solutions are preferably sprayed into a reactor, at which time the alkylisothiocyanate formed distills off in vapor form and an aqueous phase containing the byproducts collects in the reactor. The method is capable of significantly increasing the space-time yield because much less sulfur is formed in comparison to the previously known method, which takes place at pH 5 to 9, thereby minimizing the shutdown times previously required for cleaning the reactor.

Abstract: A heavy concentration of volatile substances and high degree of purity are achieved in a short time in a closed system by transferring the volatile substances from a vessel containing the gas phase into a condensation vessel by means of a capillary with a small inner diameter. Preferably there is a temperature drop from the vessel containing the gas phase to the condensation vessel.

Abstract: Methyl isocyanate is prepared by reacting an alkali cyanate with dimethyl sulfate in the presence of an alkaline earth metal oxide and in an inert organic liquid. There can also be present an alkali metal or alkaline earth metal salt.

Abstract: Isothiocyanates of the formula (I)r -- n.dbd.c.dbd.s (i)in which R is a straight or branched alkyl group with 1 to 18 carbon atoms, preferably methyl, and wherein the alkyl group can be substituted once or more by --OH, --OR.sup.1 or --SR.sup.1 and where R.sup.1 is an alkyl group of 1 to 6 carbon atoms or R is cycloalkyl with 3 to 8 carbon atoms, benzyl or phenyl in which the aromatic nucleus can be substituted once or more by a chlorine atom, a bromine atom, a hydroxyl group, or --R.sup.1, --OR.sup.1 or --SR.sup.1 or R is a pyridyl or thiazolyl group prepared by reacting (1) a dithiocarbamate of the general formula (II) ##STR1## where R is as defined above and Me is an alkali atom, one valence of an alkaline earth metal atom or the ammonium group whose hydrogen atoms can be substituted by R with (2) a cyanogen halide, preferably cyanogen chloride, in the presence of water.