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改进了BAH重要中间体3-(2-氨基-2-硫代乙基)苯甲酸甲酯的合成工艺。以苯甲酸甲酯为原料,通过氯甲基化、氰化和硫代三步反应合成3-(2-氨基-2-硫代乙基)苯甲酸甲酯。采用多聚甲醛和氯化氢作为氯甲基化试剂,通过多氯甲基副产物的循环,抑制多氯甲基化副反应,3-氯甲基苯甲酸甲酯收率可达85.3%;在水相中进行氰化反应,3-氰甲基苯甲酸甲酯收率达90.2%;以硫化氢为硫代试剂,在新型水/脒类盐酸盐的溶剂/催化剂体系中,结合滤液循环工艺,3-(2-氨基-2-硫代乙基)苯甲酸甲酯收率可达98.6%;三步反应总收率75.9%。 相似文献
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二硫化二苯并噻唑的催化合成 总被引:1,自引:0,他引:1
以2-巯基苯并噻唑和氨水为原料,双氧水作氧化剂,经催化剂A进行催化,合成了二硫化二苯并噻唑。通过考察催化剂种类、催化剂用量、氨水用量、物料配比、反应时间和反应温度对产率的影响,得出适宜的工艺条件为:选用催化剂A,用量为2-巯基苯并噻唑的1%,氨的加入量为n(2-巯基苯并噻唑)∶n(氨水)=1∶6.0,双氧水用量为n(2-巯基苯并噻唑)∶n(双氧水)=2∶1.2,反应时间3 h,反应温度50℃。在此条件下,二硫化二苯并噻唑的产率为90.7%,熔点为165.3~168.7℃。二硫化二苯并噻唑粗品通过甲苯进行一次重结晶后,熔点可达173.6~175℃。 相似文献
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《精细化工原料及中间体》2005,(4):41-42
根据酰化剂的种类和组分,苯并噁唑-2-硫酮和苯并噻唑-2-硫酮用醋酐和酰基氯进行酰化作用生成N-酰基和/或S-酰基衍生物。苯并噁唑-2-硫酮用芳烷基氯碳酸酯进行烷氧基羰基化作用主要生成N-烷氧基羰基衍生物。而苯并噻唑-2-硫酮用芳烷基氯碳酸酯进行烷氧基羰基化作用,仅仅生成S-烷氧基羰基衍生物。在醇存在下,N-酰基衍生物光解生成苯并噁唑-2-硫酮或苯并噻唑-2-硫酮和酯。 相似文献
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本文利用线性电势扫描的方法研究了几种苯并噻唑类化合物及巯基苯基四氮唑在银上的吸附机理。结果表明:2.巯基苯并噻唑和巯基苯基四氮唑以化学吸附方式,通过分子上巯基与银表面的作用形成分子紧密排列的吸附层。25℃下,PMT可以在银表面形成紧密单层。这种吸附在较高吸附温度下可以转化为多层,且完全覆盖银表面。在含Br~-的溶液中,它可以阻碍Br~-与表面的接触。在较大的浓度下,2-甲基苯并噻唑和苯并噻唑也可以在银表面的某些位置,通过杂环上的S原子(或N原子)形成松散的吸附,但这种吸附层不能完全覆盖银表面。电镜实验也表明以上物质在银表面发生了作用。 相似文献
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为了寻找新的针对硫酸盐还原菌的杀菌剂,以甲硝唑(0.3m01)与溴化铵(0.39m01)和浓硫酸,在120℃,反应12h,合成了1-(2-溴乙基)-2-甲基-5-硝基咪唑(MBr);MBr(0.3m01)与硫氰酸钠(0.33m01),乙酸乙酯为溶剂,回流反应6h,合成了1-(2-硫氰基乙基)-2-甲基-5-硝基咪唑(MSCN);然后MSCN(0.3m01)与氯化苄(0.3m01),100℃,反应2h,合成了一种新型药剂1-(2-硫氰基乙基)-2-甲基-5-硝基咪唑-3-苄基氯化铵(B)。评价了化合物B对硫酸盐还原菌杀菌性能,其最低抑菌浓度(MIC)〈30mg/L,甲硝唑的MIC〉60mg/L,其杀菌性能比甲硝唑有很大提高。 相似文献
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2-(4-Morpholinothio)benzothiazole (MOR) and 2-(4-morpholinodithio)-benzothiazole (MDB) were reacted, in combination with sulfur and ZnO, in the presence of polyisoprene (IR). Samples were heated in a DSC at 2.5°C/min and characterized by swelling experiments. The products formed at various temperatures were analyzed by HPLC. Crosslinking only occurred once all the benzothiazole sulfenamide had been consumed, the onset of vulcanization characterized by a considerable increase in 2-mercaptobenzothiazole (MBT) concentration. Crosslinking occurred earlier in all corresponding MDB formulations. Higher crosslink densities were recorded with addition of ZnO. The delayed action experienced in MOR systems was attributed to an exchange reaction between benzothiazole-terminated pendent groups and MOR and not due to the stability of the disulfide, MDB. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1093–1099, 1997 相似文献
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提供了一种用三氟乙氧基化反应和加氢还原制备三氟乙氧基苯胺的方法。以邻氯硝基苯和对氯硝基苯为原料,与三氟乙醇钠在120℃反应5h,制得邻位和对位两种三氟乙氧基硝基苯,收率分别为87.1%和95.8%;两种三氟乙氧基硝基苯经钯炭催化剂催化加氢还原,75℃反应1h,得目标化合物2-(2,2,2-三氟乙氧基)苯胺和4-(2,2,2-三氟乙氧基)苯胺,收率分别为94.5%和95.2%。产物结构经1HNMR和IR确证。 相似文献
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Exchange reactions between tetramethylthiuram disulfide, 2-mercaptobenzothiazole, and sulfur in the presence of ZnO were studied by heating powdered mixes to vulcanization temperatures at a preprogrammed rate in a DSC. The reaction was stopped at points along the thermal curve and the mixture was analyzed. Sulfide exchange reactions between the accelerators leads to a mixed accelerator and dimethyldithiocarbamic acid that is trapped by ZnO to give the zinc accelerator complex bis(dimethyldithiocarbamato)zinc (II). Exchange also occurs between the accelerators and ligands on both the thiuram and benzothiazole zinc accelerator complexes. Zinc complexes containing ligands of both accelerators were synthesized. These showed little interaction on being heated with sulfur, but on dissolution yielded a spectrum of products similar to that obtained in the other system containing zinc. Reactions to account for changes in the spectrum of products on heating different mixes of these curatives to different temperatures are discussed. © 1995 John Wiley & Sons, Inc. 相似文献