共查询到20条相似文献,搜索用时 31 毫秒
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由乙酰乙酸乙酯和乙二醇为主要原料,采用有机酸为催化剂,合成了苹果酯。研究了催化剂用量、原料配比和反应时间对反应收率的影响。确定了反应条件:原料配比为1:1.3,催化剂用量为0.65g,反应时间5h,产物收率可达88.5%,纯度98.5%。 相似文献
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以黄磷、锌粉、硫酸和甲醛为原料,成功合成了四羟甲基硫酸鳞(THIS),详细探讨了不同合成条件对THIS产率的影响,并通过正交实验确定最佳合成工艺为:黄磷:锌粉:硫酸:甲醛=1:2.5:7.5:5(摩尔比),反应温度为85℃,反应时间为6h。建立了测定其活性物含量的离子交换法,测得THIS的含量为79.20%。用36%乙酸对产品进行重结晶,成功得到了THIS针状晶体。 相似文献
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研究了以对硝基苯胺为原料,在催化剂的作用下,合成2-氨基-6-硝基苯并噻唑。其适宜的工艺条件为:n(对硝基苯胺):n(硫氰酸胺):n(苯)=1:1.15:6.5,反应温度为80-85℃,反应时间为10h;n(对硝基苯基硫脲):n(催化剂)=1:0.093,室温反应,反应时间为2h。产品收率为64.5%,纯度≥99%。 相似文献
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PEG活化固体超强碱催化合成茴香醇 总被引:1,自引:0,他引:1
对甲氧基苯甲醛与甲醛的Carmizzam反应合成茴香醇工艺进行了改进。采用KF/γ-Al2O3固体超强碱催化剂、PEG为催化活化剂的工艺路线,提高了产物的收率。最佳工艺条件为对甲氧基苯甲醛:36%甲醛:KF/γ-Al2O3:PEG=1.0:1.5:0.03:0.1,反应时间1.5h,反应温度60%,所得的茴香醇的产率可达71%。催化剂KF/γ-Al2O3具有较高的催化活性,易于回收,可重复使用5次以上。 相似文献
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微波诱导稀土固体超强酸SO4^2-/TiO2/Ce^4+催化合成乙酸正丁酯 总被引:7,自引:1,他引:7
本文探讨了标题合成方法中合成反应条件对酯收率的影响。其最佳反应条件为:n(醇):n(酸)=2.5:1.0,固体超强酸用量为反应物总质量的2.0%,微波辐射功率528W,辐射时间20min,酯收率达89.5%。用IR等手段对产品进行了确证。 相似文献
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快速发展无毒柠檬酸三丁酯的生产和应用 总被引:10,自引:0,他引:10
采用柠檬酸和正丁醇在复合催化剂存在的情况下,合成了柠檬酸三丁酯。酯化反应的最佳条件为:n(正丁醇):n(柠檬酸)为3.5:1.反应温度100~130℃,催化剂用量为柠檬酸质量的0.8%.反应时间2.8h。酯化率达到99.4%以上,产品纯度大于99.5%;同时对柠檬酸三丁酯的性质及用途进行了介绍。 相似文献
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从纤维结构及染色工艺对阳离子染料可染涤纶纤维的染色性能进行了研究。探讨了染料用量、pH值、匀染剂用量、和染色时间对染色的影响。通过对比试验得出最佳染色处方和工艺条件为:染料用量0.5%(o.w.f),pH值3.5—4.5,醋酸钠1%(o.w.f),匀染剂12270.5%(o.w.f),浴比1:30,100%染100分钟... 相似文献
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Once merely thought of as the protein responsible for the overall physical nature of the human immunodeficiency virus type 1 (HIV-1), the Gag polyprotein has since been elucidated to have several roles in viral replication and functionality. Over the years, extensive research into the polyproteins’ structure has revealed that Gag can mediate its own trafficking to the plasma membrane, it can interact with several host factors and can even aid in viral genome packaging. Not surprisingly, Gag has also been associated with HIV-1 drug resistance and even treatment failure. Therefore, this review provides an extensive overview of the structural and functional roles of the HIV-1 Gag domains in virion integrity, functionality and infectivity. 相似文献
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Ignacija Vlai Anela Horvat Ana Tadijan Neda Slade 《International journal of molecular sciences》2023,24(1)
Metastatic melanoma is one of the most aggressive tumors, with frequent mutations affecting components of the MAPK pathway, mainly protein kinase BRAF. Despite promising initial response to BRAF inhibitors, melanoma progresses due to development of resistance. In addition to frequent reactivation of MAPK or activation of PI3K/AKT signaling pathways, recently, the p53 pathway has been shown to contribute to acquired resistance to targeted MAPK inhibitor therapy. Canonical tumor suppressor p53 is inactivated in melanoma by diverse mechanisms. The TP53 gene and two other family members, TP63 and TP73, encode numerous protein isoforms that exhibit diverse functions during tumorigenesis. The p53 family isoforms can be produced by usage of alternative promoters and/or splicing on the C- and N-terminus. Various p53 family isoforms are expressed in melanoma cell lines and tumor samples, and several of them have already shown to have specific functions in melanoma, affecting proliferation, survival, metastatic potential, invasion, migration, and response to therapy. Of special interest are p53 family isoforms with increased expression and direct involvement in acquired resistance to MAPK inhibitors in melanoma cells, implying that modulating their expression or targeting their functional pathways could be a potential therapeutic strategy to overcome resistance to MAPK inhibitors in melanoma. 相似文献
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本文在常用制备导电高分子复合材料的原材料配方的基础上,加入新型抗氧化剂A、消泡剂B,目的是在保持导电高分子复合材料力学性能的基础上,显著提高其导电性能,满足实践需要。实验证明当金属填料含量达到某一最佳比例时,其力学性能和电学性能均能达到预期目的。 相似文献
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