Direct polycondensation of hydroxybenzoic acids with thionyl chloride in pyridine

The reaction promoted by thionyl chloride and pyridine could selectively activate carboxyl groups of hydroxybenzoic acids to give polyesters of high inherent viscosities up to 3.8. Favorable conditions were studied in terms of the temperatures for the initial reaction with the acids and subsequent aging at room temperature. Copolymers of several combinations of hydroxybenzoic acids with high molecular weights were obtained in quantitative yield by carrying out the polycondensation at 80°C for 3 h. The reaction could also produce high molecular polyesters in a simpler process without the initial activation of dicarboxylic acids by adding a mixture of these monomers to the condensing agent, and a tough film- and fiberforming polymer was obtained from 4,4′-dihydroxyphenylsulfone of low nucleophilicity whose polymer of high molecular weight is difficult to obtain. The process was also successfully applied to the direct copolycondensations of hydroxybenzoic acids, aromatic dicarboxylic acids, and bisphenols to produce polyesters of η_inh up to 5.6.     

An oxidation with thionyl chloride

The reaction of the 2-methylquinoline-3-carboxylic acid 1b with thionyl chloride gave the dichlorothiolactone 2 , the structure of which was confirmed by chemical transformations.     

Direct polyamidation with phosphorus oxychloride in pyridine

Direct polycondensation of aromatic dicarboxylic acids and diamines with phosphorus oxychloride (POC) was successfully carried out to give polyamides of high inherent viscosity, when POC was reacted selectively and completely with a two molar quantity of carboxyl groups. To achieve the selective and complete reaction, factors, such as the amount of POC used, reactions of POC with the dicarboxylic acids by adding of POC to the acids or its reverse addition under various conditions, and aging after addition were fully examined. The reaction was proposed to proceed via a bifunctional cyclic phosphoric–carboxylic anhydride through stepwise reaction of POC with carboxyl groups.     

Reactions of salicylamides with thionyl chloride

A series of compounds having the 1,2,3-benzoxathiazin-4 (3H) one 2-oxide structure have been synthesized by the interaction of thionyl chloride with the appropriate salicylamide. Some properties of these compounds as well as some by-products are described.     

Direct polyesterification with thionyl chloride in pyridine improved by a modification of monomer sequences in copolymers

The direct polyesterification with thionyl chloride (SOCl₂) in pyridine was further investigated. Copolycondensations of dicarboxylic acids, bisphenols, and hydroxybenzoic acids were significantly affected by the reaction temperatures and combinations of monomers which could change relative rates of alcoholyses of the activated dicarboxylic acids and the hydroxyacids consequently to vary monomer sequences in the copolymers resulted. The sequences were tried to be varied more directly by stepwise reactions of monomers in copolycondensations of dicarboxylic acids, bisphenols, and p-hydroxybenzoic acid (PHB), as well as PHB and m-hydroxybenzoic acid (MHB). The reactions proceeded smoothly and satisfactorily when carried out by initial reaction of dicarboxylic acids and PHB followed by bisphenols likely to favor sequential to random distributions of monomers. Reverse addition of PHB and bisphenols, and then dicarboxylic acids resulted in rapid precipitation due to some oligomerization of PHB at an earlier stage of reaction, and largely retarded the reaction. This was also the case for the copolycondensation of PHB and MHB. Copolymers of high inherent viscosities with up to 65 mol% PHB could be obtained by initial reaction of MHB followed by PHB.     

Reaction of 2-thiobenzazoles with thionyl chloride

A new reaction in the benzimidazole series, viz., replacement of the mercapto group by chlorine by the action of thionyl chloride on 2-thiobenzimidazoles, was discovered. Benzoxazolone is formed by treatment of 2-thiobenzoxazole with thionyl chloride, and 2,2-dithiobis(2-benzothiazole) is formed from 2-thiobenzothiazole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1047–1050, August, 1985.     

Direct polyesterification with thionyl chloride in pyridine improved by a modification of monomer sequences in copolymers

The direct polyesterification with thionyl chloride (SOCl₂) in pyridine was further investigated. Copolycondensations of dicarboxylic acids, bisphenols, and hydroxybenzoic acids were significantly affected by the reaction temperatures and combinations of monomers which could change relative rates of alcoholyses of the activated dicarboxylic acids and the hydroxyacids consequently to vary monomer sequences in the copolymers resulted. The sequences were tried to be varied more directly by stepwise reactions of monomers in copolycondensations of dicarboxylic acids, bisphenols, and p-hydroxybenzoic acid (PHB), as well as PHB and m-hydroxybenzoic acid (MHB). The reactions proceeded smoothly and satisfactorily when carried out by initial reaction of dicarboxylic acids and PHB followed by bisphenols likely to favor sequential to random distributions of monomers. Reverse addition of PHB and bisphenols, and then dicarboxylic acids resulted in rapid precipitation due to some oligomerization of PHB at an earlier stage of reaction, and largely retarded the reaction. This was also the case for the copolycondensation of PHB and MHB. Copolymers of high inherent viscosities with up to 65 mol % PHB could be obtained by initial reaction of MHB followed by PHB.     

Lithium-lithium tetrachloroaluminate reference electrode in thionyl chloride

Three in situ techniques for charging current compensation (c.c.c.) in d.c. polarography are described. These methods envisage the superposition of an a.c. ripple and analogue processing of the response to yield a quantity proportional to the d.c. charging current. The theory of these procedures outlined in this paper, enables one to approach c.c.c. without any reliance on trial and error. Details of the appropriate circuitry and supporting experimental verification of the theory are also presented.     

Polymerization of N-vinylcarbazole by thionyl chloride

The polymerization of N-vinylcarbazole (NVC) initiated by SOCl₂ in benzene and nitrobenzene solvents was studied at 32°C. R_p is first order with respect to SOCl₂ concentration and also to NVC concentration up to a certain NVC concentration, after which it falls. Rate and the molecular weight increase with increasing dielectric constant of the medium. The rate and molecular weight are depressed by the addition of amines, thiophene, and water. The degree of polymerization is independent of SOCl₂ and NVC concentration. A conventional cationic mechanism has been suggested, and a suitable kinetic scheme has been proposed in conformity with the findings.     

Synthesis of hindered hydrazones and their reaction with thionyl chloride

Hydrazones 12a–c and ketazines 13a–c were prepared by the reaction of ketones 11a–c with hydrazine hydrate depending on the temperature and the reaction time. Some ketone (aryl)hydrazone derivatives 14a,c,e reacted with thionyl chloride to afford the chlorothiadiazoline derivatives 15a–c . Surprisingly, the chlorine atom in the latter compounds was found to undergo smooth nucleophilic substitution, and by boiling these compounds in absolute ethanol gave the corresponding ethoxythiadiazoline derivatives 16a–c . The structure of the ethoxythiadiazoline 16b was confirmed by single crystal X‐ray determination. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:223–228, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10125     

Nuclear quadrupole coupling constants of thionyl chloride

The nuclear quadrupole structure of some low J transitions with large splittings has been measured for thionyl chloride (SO³⁵Cl₂) and analysed in terms of a first order perturbation. The following nuclear quadrupole coupling constants were obtained: x_aa = ?25.01 ± 0.07 MHz, x_bb = ?0.03 ± 0.45 MHz and x_cc = 25.04 ± 0.45 MHz.     

A novel reaction of thionyl chloride with 3-aryl-2,1-benzisoxazoles

Novel reductive chlorination of 3-aryl-2,1-benzisoxazoles with thionyl chloride is described. The chlorinated aminobenzophenones have been characterised.     

亚硫酰氯还原的电催化研究

利用碳粉微电极和显微Raman分子探针技术研究了SOCl~2阴极还原的电催化性能.在八硫杂氢化酞菁的催化作用下, SOCl~2还原过程中的产物硫将进一步还原.碳粉微电极表面沉积物形貌和Raman光谱分析表明硫是引起电极钝化的另一个重要因素,催化剂存在的条件下,硫进一步还原的结果是使碳表面有不同程度的活化,这对提高电池容量和电压有较大影响.     

Preparation of aromatic polyesters by direct polycondensation with thionyl chloride in pyridine

Mechanistic features of the reaction with thionyl chloride in pyridine were studied in a model reaction of benzoic acid with p-chlorophenol or aniline. The yields were significantly affected by the amounts of pyridine, favorably by four equivalents, and the nature of pyridine, suggesting that pyridines are not only HCl scavengers, but are also involved in the reaction itself. The reaction was assumed to proceed via a carboxylic sulfinic-anhydride intermediate different from acyl chloride, and the intermediate was found to be not so reactive that it was completely alcoholyzed by the phenol at high temperatures of more than 60°C. The reaction was successfully applied to the preparation of aromatic polyesters of high molecular weights by the direct polycondensation of aromatic dicarboxylic acids and bisphenols in pyridine at 80°C.