反应率

According to the electrophilic substitution of α-Allocryptopin by ICl, it can be suggested that there are competitions of n-donors (such as N and O atom occurred in alkaloid or solvent molecules) with the conjugated π system in alkaloid molecule for iodine monochloride when charge-transfer complexes are formed, which may block the formation of pre-reactive π-complex intermediate, and thus suppress the electrophilic substitution.

这一方法标记过程简便，标记产物富集于有机相，易于进一步纯化，其放射化学纯度接近95%，标记率超过70%；ICl与α-别隐品碱的亲电碘化反应结果表明，生物碱底物或溶剂分子中的N、O等n电子给体可能与亲电试剂形成电荷转移络合物，竞争芳香亲电取代反应π络合物反应前体的形成，从而抑制碘化反应的发生。

Whenpyridine was used as reductive decomposing agent, the expecting cholest-4-en-3,6-dione-22-al was obtained. However, when Zn/HOAc was used to decomposethe ozonide, C-4,5 double bond was further reduced to give cholest-3,6-dione-22-al as main product. 2 For the side-chain construction of compound (1), the solid-liquid phase-transfer Wittig reaction was used. When (3-methyl-2-oxobutyl)-triphenylarsonium bromide was used as reagent, the reaction can be carried out inmild reaction condition and the yield is higher than that when phosphorane wasused.

但使用Zn／HOAc作为分解剂时，却得到其氢化产物胆甾-3， 6-二酮-22-醛；2在甾体支链引入过程中，采用固-液相转移Wittig反应的方法，用(3-甲基)-2-氧丁基三苯基溴化胂作为试剂，反应在非常温和的条件下便可完成，而且产率比传统采用膦烷的方法更高；3在对某些甾酮化合物的选择性还原反应研究时，发现在〓还原体系中，当加入某些金属离子后，反应有更好的区域选择性和立体选择性。

The results showed that the yield of phenyl glycidyl ether was 96.8% when the mole rate of sodium phenolate and epichlorohydrin was 1.15:1, the mass ratio of ionic liquid and reactant 2:1, reaction temperature 70℃ and reaction time 2h.

结果表明，在反应温度为70℃，反应时间为2h，反应物苯酚钠与环氧氯丙烷的物质的量比为1.5：1，离子液体与反应物的质量比为2：1时，苯基缩水甘油醚的产率为96.8%。

Vanillin 58 was used as starting material, which underwent methylation, bromination, acetalization, lithiation followed by nucleophlic addition to aldehyde, Diels-Alder reaction, selective reduction and lactonization to produce diphyllin in an overall yield of 38%(7 steps).

这个方法从香兰素58开始，经过甲基化、溴化、成乙二醇缩醛反应、锂化而后对醛亲核加成、Diels-Alder反应、选择性还原反应和内酯化反应共7步，最后得到diphyllin，总产率38％。

This paper details an efficient method for a one-step transformation of the trityl ether to the acetonide. Treatment of trityl ether with a mixture of trifluoroacetic acid, 2,2-dimethoxy propane and camphorsulfonic acid as catalyst in dichloromethane through detritylation followed by acetonization gave the acetonide in high yield.

介绍了一种新的高效的由三苯甲基醚直接生成丙酮化合物的方法，也就是使三氟乙酸条件下脱三苯甲基的反应和生成丙酮化合物的反应在一个反应瓶中同时进行，使脱三苯甲基作用后生成的醇继续反应得到高产率的丙酮化合物。

The main work we did on synthesis: We studied bromination reaction influence factor in detail, such as reaction time、reaction temperature、solvent dosage、reagent mole ratio, and optimized the reaction condition, discussed reaction mechanism rudimentally.

本文在合成方面所做的工作：系统研究了对称二醇的单溴代反应反应时间、反应温度、溶剂用量、反应物摩尔比等因素对产率的影响。

It showed that the ammonium ferric sulfate dodecahydrate was an excellent catalyst,the yield of the n-butyl lactate could reach over 95.0% under molar ratio of n-butyl alcohol and lactic acid 2.25∶1,the reaction temperature of 110～125℃,reaction time of 1.5 h and amount of the ammonium ferric sulfate dodecahydrate catalyst of 2.5%.

实验表明：NH4Fe(SO4)212H2O是合成乳酸正丁酯的良好催化剂。最佳反应条件为：醇酸物质的量比2.25∶1，催化剂的用量为反应物料总量的2.5％，酯化反应时间为1.5 h，反应温度110～125℃，酯化率可达95.0％。

To improve the selectivity, the Co/Mn/Br catalyst system with ethanal as an additive was studied and the reaction conditions were also optimized, which were as follows:the amount of ethanal 10%(mole ration base on the substrate), reaction temperature 100℃,reaction time 30min,the oxygen pressure 0.2MPa, the amount of the composite catalyst Co/Mn/Br 7%,the mass ration of different ingredients 2:2:1. Under these conditions, the yield comes to 24.10% and the selectivity reaches 75.03%.

为了提高反应的选择性，论文初步研究了以乙醛作为添加剂条件下各工艺参数的影响，并进行正交优化，得出最佳条件为：乙醛加入量1：10，反应温度100℃，反应时间30min，氧气压力0.2MPa， Co/Mn/Br混合催化剂加入量7%，质量比2：2：1，在此条件下，反应产率为24.10%，选择性可达75.03%。

The hydrogenation and methyl esterification of furoic acid over Pd-Ni/γ-Al2O3 catalysts was investigated in fixed bed micro-reactor under different conditions such as reaction temperature,pressure,H2 space velocity,space velocity of furoic acid and methol,ratio of H2 and furoic acid and so on.

以糠酸、甲醇、氢气为原料，采用连续流动固定床微反应器，Pd-Ni/γ-Al2O3为催化剂，使糠酸一步加氢甲酯化生成α-四氢糠酸甲酯。研究了反应的温度，压力，气、液体流速，进料流量等因素对催化反应的影响。结果表明：在1.5MPa，250℃，氢气空速3300 h-1，液体空速3.0 h-1(氢油比为50)时，糠酸转化率为96.6%，四氢糠酸甲酯的选择性97.2.0%，产率94.0%。催化剂稳定性较好，连续运转280小时后未见活性下降。该反应体系活性高，选择性好，反应压力低，催化剂性能稳定，操作简单，产物易分离

These compounds are of substantial interest both inviewpoints of theory and practical applications, mainlyunder the stimulus to achieve synthetic models either foractive sites of iron-sulfur proteins or for transitionmetal catalysts. This thesis describes the synthesis, structures andconformations of 51 new iron-sulfur cluster complexes,which have been characterized by elemental analysis andstandard spectroscopic methods. In addition, single-crystalX-ray diffraction analyses were performed for 4 representa-tive new compounds. Reactivities of μ-〓 with mono- and di- Grig-nard reagents derived intermediates toward various organicelectrophilic substrates were studied, along with complexa-tion of arynyl-containing iron-sulfur clusters by 〓Thus, several bridged, non-bridged, monomeric, dimeric,homonuclear, heteronuclear iron-sullfur and iron-sulfur co-balt-carbon cluster complexes were synthesized. A novelreaction and convenient route for the synthesis in highyield of tetranuclear iron complexes 〓 containing atetracoordinated sulfur atom was discovered, whereas aplausible mechanism based on experimental results was propo-sed for the formation of the new cluster type.

鉴于有机铁硫原子簇化学在基础理论发展和应用方面的重要意义，因此我们开展了这一课题的研究，并取得以下主要成果： 1、本文共合成了51个新有机铁硫及含钴碳簇基的有机铁硫原子簇配合物，除用元素分析，NMR，IR，MS法表征其结构和构象外，还用X-光衍射技术测得四个代表性配合物的单晶结构和构象； 2、我们业已发现炔基Grignard试剂同〓可形成一种&开环&与&闭环&中间物的平衡混合物，研究该平衡混合物同各种亲电试剂的反应； 3、研究发现了一种可高产率地形成〓含〓四配位硫挛合簇的新化学反应并对此反应提出了—种有趣的反应机理； 4、首次由1，4-二溴丁烷双Grignard试剂与〓制得一种新型铁硫簇双硫阴离子活性中间体，并进而研究了它的亲核反应性能； 5、找到了通过〓的光化学反应来合成簇合物〓-〓的一条有实用价值的新路线。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。