Reference

Thermochemistry of 2,5-Thiophenedicarboxylic Acid

All Rights Reserved. Thermochemistry of 2,5-Thiophenedicarboxylic Acid. Roux, Maria Victoria; Temprado, Manuel; Jimenez, Pilar; Foces-Foces, Concepcion; Notario, Rafael; Verevkin, Sergey P.; Liebman, Joel F. ( Instituto de Quimica Fisica Rocasolano, CSIC, Madrid 28006, Spain). Journal of Physical Chemistry A, 110(45), 12477-12483 (English) 2006 American Chemical Society. CODEN: JPCAFH. ISSN: 1089-5639. DOCUMENT TYPE: Journal CA Section: 22 (Physical Organic Chemistry) Section cross-reference(s): 69 The enthalpies of combustion and sublimation of 2,5-thiophenedicarboxylic acid [CAS RN 4282-31-9] were measured by rotary-bomb combustion calorimetry and the method of transference in a satd. stream of nitrogen, and the gas-phase enthalpy of formation was detd., DfHom(g) = -(632.6 ± 2.2) kJ·mol-1. Std. ab initio MO calcns. at the G2(MP2) and G3(MP2) levels were performed, and a theor. study on the mol. and electronic structure of the compd. has been carried out. The three most stable conformers have been explicitly taken into account. The calcd. enthalpy of formation averaged using three different isodesmic reactions, -631.1 kJ·mol-1, is in very good agreement with the exptl. value. A comparison of the substituent effect of the carboxylic groups in benzene and thiophene ring has been made. The relative stability obtained for the substitution of two H atoms by COOH in position 2,5- for thiophene and 1,4- for benzene involve the same energetic effects, DDfHom = -747.6 ± 2.4 and -748.2 ± 2.7 kJ·mol-1, resp.

Method for synthesis of thiophene-2,5-dicarboxylic acid

All Rights Reserved. Method for synthesis of thiophene-2,5-dicarboxylic acid. Zhang, Shengjian (Ningbo Institute of Technology, Zhejiang University, Peop. Rep. China). Faming Zhuanli Shenqing Gongkai Shuomingshu CN 1876645 A 13 Dec 2006, 5pp. (Chinese). (People's Republic of China). CODEN: CNXXEV. APPLICATION: CN 2010-49965 23 Mar 2006. DOCUMENT TYPE: Patent CA Section: 27 (Heterocyclic Compounds (One Hetero Atom)) Thiophene-2,5-dicarboxylic acid was prepd. from adipic acid and thionyl chloride with the presence of catalytic amt. of pyridine, heating to 85-95° and keeping the temp. for 10-18 h, removing excess thionyl chloride and heating again the reaction soln. to 100-130°, keeping the temp. for 1-3 h, after that dropping an aq. 1313-82-2 and 4282-31-9 which are cas registry numbers of chemicals are mentioned. soln. contg. 2-6 mol base and 1-2 mol sulfide at 60-98°, heating again to 85-98°, keeping the temp. for 2-6 h, finally adding an inorg. acid to adjust the pH value and ppt. the crude product. The method has the advantages of high product yield, low cost, and no carbon aggregation. .