Degussa Aktiengesellschaft

Deutsche Gold- Und Silber-scheideanstalt Vormals Roessler

Bayer Aktiengesellschaft

Asta Medica, Aktiengesellschaft

Ciba-geigy Corporation

Herbert Klenk

Heribert Offermanns

Axel Kleemann

Werner Schwarze

Klaus Huthmacher

Harald Jakob

Horst Bethge

Thomas Beisswenger

Theodor Lussling

Hans B Wagner

Frank Hubner

Roland Moller

Alfred Maierhofer

Thomas Haas

Helmut Waldmann

Dietrich Arntz

Hermann Seifert

Paul Scherberich

Stephan Rautenberg

Rolf Wirthwein

Rainer Gewald

Alfred Olbrich

Gerhard Sator

Armin Neher

Walter Girke

Willy Meyer

Georg Pissiotas

Willi Hofen

Gerd Schreyer

Wulf Schwerdtel

Horst Weigel

Wolfgang Leuchtenberger

Wolfgang Swodenk

Joachim Goede

Hans-Joachim Hasselbach

Otto Weiberg

Dieter Most

Bernd Lehmann

Gerd Siekmann

Karl-Hermann Reissinger

Axel Kleeman

Gunes Giray

Bernd Lehamnn

Wolfgang Leuchtenberg

Wolfgang Schulz

The invention relates to the production and purification of salts of 6,8-bis (amidiniumthio)octanoic acid, its enantiomers (+)-6,8-bis(amidiniumthio)octanoic acid and (-)-6,8-bis (amidiniumthio)octanoic acid and of the esters of these compounds as well as to their use to produce dihydrolipoic acid and .alpha.-lipoic acid.

Production and use of salts of 6,8-bis (amidiniumthio)-octanoic acid

The invention relates to the production and purification of salts of 6,8-bis(amidiniumthio) octanoic acid, its enantiomers (+)-6,8-bis(amidiniumthio)octanoic acid and (-)-6,8-bis (amidiniumthio)octanoic acid and of the esters of these compounds as well as to their use to produce dihydrolipoic acid and .alpha.-lipoic acid.

Production and use of salts of 6, 8-bis (amidiniumthio) -octanoic acid

RS-thioctic acid with a novel morphology which is obtained by a recrystallization process.

RS-thioctic acid with novel morphology

A process is described for the simultaneous production of 1,2- and 1,3-propanediol from glycerol. The process involves the reaction stages (a) dehydration of glycerol by feeding a gaseous glycerol-water mixture with 10 to 40 wt % glycerol at 250.degree. to 340.degree. C. over a solid catalyst with an H.sub.0 value (Hammett acidity function) of less than 2, preferably between -3 and -8.2, (b) hydration of the acrolein contained in the reaction mixture of stage (a), and (c) catalytic hydrogenation of the reaction mixture, containing 3-hydroxypropionaldehyde and hydroxyacetone, of stage (b). Two valuable products, namely 1,2- and 1,3-propanediol, can be obtained simultaneously and in high total yield from glycerol in a simple process.

Process for the simultaneous production of 1,2- and 1,3-propanediol

A process for the production of acrolein by dehydration of glycerol in the liquid phase or in the gaseous phase, in each case on acidic solid catalysts, is described. Compared with previously known processes, the space-time yield and catalyst service life may be surprisingly increased with higher selectivity by treating a glycerol-water mixture with a glycerol content of 10 to 40 wt. % at 180.degree. to 340.degree. C. (liquid phase) or at 250.degree. to 340.degree. C. (gaseous phase) on a solid catalyst with an H.sub.o value (Hammett acidity function) of less than +2, preferably less than -3.

Process for the production of acrolein

Optically active salts are disclosed of the formula (I): ##STR1## wherein Ac represents an acyl group, R.sup.1 hydrogen or methyl, R.sup.2 and R.sup.3 identical or different substitutes, preferably methyl. The salts can be obtained from the corresponding optically active carbonic acid and DL-3-cyano-2-hydroxypropyl trimethylammonium hydroxide. The diastereomeric salt pairs are easily split from one another and separated again, so that the process is suited for producing optically active 3-cyano-2-hydroxypropyl trimethylammonium salts.

Optically active salts of a substituted thiazolidine-4-carboxylate and

Synthesis of L-carnitine by chemical optical resolution of D,L-carnitine nitrile salts, where the D,L-carnitine nitrile salt is reacted with optically active N-acetylproline as the resolving agent in order to form the diastereomer salts after conversion to the hydroxide form, one of the two diastereomer salts is separated by fractional crystallization and the fraction containing mainly L-carnitine nitrile salt is treated with an optically inactive strong acid in order to split off the optically active N-acetylproline and then the resolving agent is separated and the resulting L-carnitine nitrile salt is saponified to L-carnitine. N-acetyl-L-proline is used as the resolving agent and the diastereomer (LL) salt is obtained in crystalline form in a high optical purity by fractional crystallization and the L-carnitine nitrile salt obtained after splitting off and separating N-acetyl-L-proline is used directly for saponification without further crystallization.

Process for producing L-carnitine from D,L-carnitine nitrile salts

Aqueous solutions of free, neutral .alpha.-amino acids are recovered from aqueous solutions of their alkali-metal salts. Two equally large rectifying columns filled with a strongly acidic cation exchanger in the H.sup.+ form are used, the discharge of the first column being connected to the head of the second column. The solution of the alkali-metal salt is at first delivered to the head of the first column, then the residual solution, reduced by the alkali-metal cations adsorbed in the exchanger, is displaced to the second column by means of the addition of water. A product-free forerun is first separated at the discharge of the second column and, when free .alpha.-amino acid begins to exit in the flow-off from the second column, the receiver is changed and the delivery of water to the head of the first column continues further until a mixed pH between 5 and 7 has been achieved in the receiver. Then, the previously first column is decoupled and regenerated, the previously second column, which is now the first column, is coupled to a freshly regenerated column as second column and the entire process is repeated as often as desired.

Method for the recovery of aqueous solutions of free, neutral

The invention relates to the preparation of optically active salts of the general formula ##STR1## from which the corresponding optically active 3-chloro-2-hydroxypropyltrimethyl ammonium chloride can be obtained by treatment with mineral acid. The L(-) form of this compound is a valuable component for the synthesis of L(-) carnitine.

A method of preparing m-trifluoromethylphenyl acetonitrile of the formula ##STR1## in which m-trifluoromethyl toluene is reacted with cyanogen chloride in the gas phase at 600.degree. to 750.degree. C.

Method of preparing m-trifluoromethylphenyl acetonitrile

To produce thiosemicarbazide hydrazine is reacted with hydrogen cyanide and sulfur to form hydrazine thiocyanate, and this is then converted into the thiosemicarbazide at an elevated temperature. Advantageously, the reaction is carried out in a polar solvent.

Process for the production of thiosemicarbazide

2-Amino-5-mercapto-1,3,4-thiadiazoles can be produced in very high yields from thiosemicarbazides and carbon disulfide in aqueous phase by working in the presence of the corresponding ammonium salt of bis-2,5-mercapto-1,3,4-thiadiazole at a temperature above 40.degree. C. Preferably the process is carried out in the presence of the mother liquor from a previous reaction.

Process for the production of 2-amino-5-mercapto-1,3,4-thiadiazole

There is provided a process for the production of .beta.-mercaptopropionic acid and its esters and nitriles by reacting the corresponding acrylic acid derivatives with trithiocarbonates in aqueous solution.

Process for the production of .beta.-mercaptopropionic acid derivatives

Herbicidally active derivatives of the formula ##STR1## in which R represents methyl, ethyl or n-propyl.

Herbicidally active 1,2,4-triazin-5-one derivatives

Caprolactones such as .epsilon.-caprolactone are stabilized against discoloration with dihydroxybenzenes such as hydroquinone or compounds of the formula ##STR1## in which R.sub.1 is alkyl of 1 to 8 carbon atoms, and

Stabilizing caprolactones with dihydroxybenzenes

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Hanau, Germany

Herbert Klenk