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研究了微波辐射下莰烯与羧酸用对甲苯磺酸作催化剂在密闭反应罐中的加成反应,系统探讨了在微波辐射下各因素对莰烯与羧酸(主要是甲酸)加成反应的影响。研究结果表明,在莰烯、甲酸和对甲苯磺酸分别为25、53和0.20mmol时,于700W功率的微波辐射下,莰烯与甲酸反应40s,反应液中甲酸异龙脑酯的含量可达77.2%,微波辐射大幅度地提高了莰烯与甲酸的加成反应速率,缩短了反应时间,为工业上莰烯的酯化工艺改进提供了新的思路。 相似文献
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2—氯对苯醌合成新工艺的研究 总被引:1,自引:0,他引:1
以邻氯苯胺为原料,重铬酸钠为氧化剂合成2-氯对苯醌,进一步探索了反应机理,优选了反应工艺条件,产品得率达到68.7%;同时对废液的回收利用提出了技术、经济上可行的办法。 相似文献
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3,7-二甲基-1,6-辛二烯(1)在固体酸(分子筛,离子膜和离子交换树脂)作用下与甲酸发生环化水合反应,生成1-(3,3-二甲基环己基)乙醇甲酸酯(4a)和3,7,7-三甲基环庚醇甲酸酯(5a)的混合物,经皂化反应得到相应的醇(4b和5b)。5,7-二甲基-1,6-辛二烯(2)在同样条件下发生类似的反应,生成3,3,5-三甲基环庚醇甲酸酯(6a)经皂化生成3,3,5-三甲基环庚醇(6b)。 相似文献
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微波辐射下莰烯与羧酸加成反应的研究 总被引:2,自引:1,他引:1
研究了微波辐射下莰烯与羧酸用对甲苯磺酸作催化剂在密闭反应罐中的加成反应,系统探讨了在微波辐射下各因素对莰烯与羧酸(主要是甲酸)加成反应的影响.研究结果表明,在莰烯、甲酸和对甲苯磺酸分别为25、53和0.20 mmol时,于700 W功率的微波辐射下,莰烯与甲酸反应40 s,反应液中甲酸异龙脑酯的含量可达77.2 %,微波辐射大幅度地提高了莰烯与甲酸的加成反应速率,缩短了反应时间,为工业上莰烯的酯化工艺改进提供了新的思路. 相似文献
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葡萄糖在甲酸体系中的降解研究 总被引:3,自引:2,他引:1
考察了55、65和75℃、反应时间0~2h条件下葡萄糖在甲酸体系中的降解情况,在甲酸中仅少量降解,在盐酸、甲酸溶液中降解较为剧烈。通过GC-MS分析75℃、反应时间4h,葡萄糖在含不同盐酸质量分数的甲酸体系中的降解产物,结果表明,在88%甲酸溶液中的主要降解产物是1,3-二羟基-2-丙酮和羟基乙醛,其降解途径是C-4位上的羟基质子化形成碳正离子的重排反应。在4%、8%盐酸、甲酸溶液中的主要降解产物是5-羟甲基糠醛,其降解途径是C-2位上的羟基质子化形成碳正离子的重排反应。 相似文献
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Summary The interaction of small, dried samples of pine, redwood and yellow-poplar with toluene, water and formic acid was measured using acoustic emission (AE) sensors. The purpose of these experiments was to determine if the level of acoustic emissions could be correlated with the amount of swelling. The results indicate that acoustic emissions are well correlated with swelling. The level of AE was low when using a non-swelling solvent, toluene, and high with water and the super-swelling solvent, formic acid. Also, it is evident that both a species effect and a solvent effect exists when the solvent/wood interaction is measured using AE.This research was performed while the primary author was an employee of the Mississippi Forest Products Laboratory 相似文献
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本文研究了萜烯苯乙烯树脂溴值的测定方法,论述了溶剂加入量、样品称量、溴酸钾—溴化钾溶液加入量、静置时间等对测定结果的影响,确定了萜烯苯乙烯树脂溴值测定的适宜操作条件。 相似文献
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Yong Sun Lu Lin Haibo Deng Hong Peng Jiazhe Li Runchang Sun Shijie Liu 《Frontiers of Forestry in China》2008,3(4):480-486
Bamboo fiber dissolution and hydrolysis in formic acid were studied. After hydrolysis, formic acid can be recovered in a clean
state and reused. Solid water-soluble sugars were obtained. After being dipped into the formic acid solution for 30 min, the
bamboo fibers started to swell. After one hour, the bamboo fibers gradually started to dissolve in the formic acid solution.
The color of the liquor/solution turned green and dark. In the end, the bamboo fibers became thoroughly dissolved in the liquor
after four hours. There was a clear hierarchical tissue structure on the fiber surface, as observed by AFM before treatment.
The differential structure disappeared after 30 min of treatment. The fiber surface became plump and glossy. After six hours
reaction at 60°C, the solid sugar mixture recovered contained glucose, cellobiose, cellotriose, cellotetrose, cellopentose
and cellohexaose. A significant fraction of the sugar products consisted of monomeric glucose. More than 54.5% of the bamboo
fiber mass had been transformed into monomeric glucose.
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Translated from Biomass Chemical Engineering, 2007, 41(2): 5–10 [译自: 生物质化学工程] 相似文献
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研究了在室温下,离子液体[Hmim][CF_3SO_3]溶解木质素及其模型化合物后,与酶液在小分子有机酸作用下形成的三元液相平衡体系,及在此体系中进行酶促反应的过程。结果表明:小分子有机酸使水-离子液体形成的两相转化为均相的主要贡献是由羧基提供的,[Hmim][CF_3SO_3]在溶解木质素后依旧保留与有机酸和水形成三元相平衡体系的能力;以酶液作为水相,以溶解了木质素的离子液体作为疏水相,甲酸的掺入在起到平衡水相和疏水相的同时也作为木质素降解酶反应过程中的自由基稳定剂;在三元液相体系的反应中,离子液体引起酶的部分失活;随着反应的进行,碱木质素和木质素脱氢聚合物(DHPs)的降解率分别为56.5%和66.5%,甲氧基分别降低了46.7%和45.3%,生成的酚类化合物分别为204.7和207.0 mg/L,甲酸分别消耗了0.57和0.76 g。DHPs在降解过程中,由于甲酸的过度消耗导致了平衡体系的解体。 相似文献
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《Wood material science & engineering》2013,8(3):157-164
ABSTRACTThis paper describes the chemical composition of sapwood (SW) and heartwood (HW) of Pinus halepensis Mill stem. Extractives were first isolated by accelerated solvent extraction and then analysed by gas chromatography-mass spectrometry (GC-MS). The cellulosic polysaccharide content present in the pre-extracted wood samples was determined with acid hydrolysis and GC. The hemicelluloses content was determined with acid methanolysis and GC. Free monomers were additionally analysed by GC. The amount of lignin was determined gravimetrically by the Klason lignin method and the acid-soluble lignin was determined by a UV method. Formic and acetic acids in wood were determined after alkaline hydrolysis and analysed by HP-SEC. It was found that lipophilic and hydrophilic extractives were more abundant in heartwood (1.6% and 2.5%) than in sapwood (1.1% and 1.8%). Celluloses content was higher in sapwood (42.5%) than in heartwood (39.7%), whereas lignin, hemicelluloses and sugar monomer contents were more abundant in heartwood (28.9%, 26.8% and 0.3%) than in sapwood (28.0%, 24.5% and 0.2%). The variation in acetic and formic acids and ash contents between sapwood (0.7%, 0.2% and 0.5%) and heartwood (0.6%, 0.1% and 0.4%) was small. The acetylation degrees were found to be slightly similar in sapwood (0.4) and heartwood (0.3). 相似文献