排序方式: 共有15条查询结果,搜索用时 15 毫秒
1.
2.
烯酮或乙烯与甲醛环加成协同反应机理的对比研究 总被引:1,自引:0,他引:1
本文研究了烯酮与甲醛, 乙烯与甲醛两个环加成反应的协同过程的过渡态(TS),用能量分解方法对两个过渡态中反应物间的相互作用能的本质做了剖析。通过对比,发现在乙烯与甲的过渡态中反应物的占有轨道间电子的交换排斥作用能比较大, 从而可以说明此反应比乙烯与烯酮间的协同过程难于进行。 相似文献
3.
4.
2,6,6-三甲基-1-烷酰基环己烯是名贵香料,本文报道通过β-环香叶酰氯与有机金属化合物(RMnI,R_2Zn,R_2Cd)合成该类化合物的新方法。产物的(IR、~1H NMR、MS)分析表明,反应过程中有双键转移发生。根据收集到的烷烃气体和对中间体的验证,提出了消除加成与亲核取代并存的反应机理。用此法合成了一系列2,6,6-三甲基-1-烷酰基环己烯,这些化合物都具有强烈而愉快的木香、花香香气。新的合成路线具有收率较好,操作简便,产物易提纯等优点。 相似文献
5.
6.
7.
8.
酰氧基甲酸酯热分解反应的量子化学研究 总被引:1,自引:0,他引:1
本文用AM1方法研究了酰氧基甲酸酯热分解反应的机理,结果表明这类化合物可消除二氧化碳得到酯,也可消除烯酮得到烷氧基甲酸,后者比前者易于进行 相似文献
9.
10.
This work presents the first investigation of a halo-carboxylic acid (Br-CH2COOH) over the surface of an oxide single crystal (the {011}-faceted TiO2(001) single crystal). A very rich chemistry is observed. This is broadly divided into three categories: elimination of HBr to make ketene, dimerisation of two molecules of ketene to 4-methyl-2-oxetanone and 1,3-cyclobutanedione, and further reaction of the latter to a mass spectrometer m/e 70 signal attributed to crotonaldehyde (formed by ring opening). Temperature programmed desorption (TPD) and Scanning Kinetic Spectroscopy (SKS) gave complementary results with SKS opening a simple way for investigating surface chemical reactions in UHV conditions with high surface coverage at still high temperatures. A successful modeling of SKS data was conducted providing the activation energies (E
a) for ketene desorption, with a reaction order n close to 1, for both CH3COOH (E
a = 21.3 kcal/mol) and BrCH2COOH (E
a = 17.2 kcal/mol). In order to further understand the surface reaction of BrCH2COOH semi-empirical PM3 computation of its adsorption and reaction on a Ti8O29H26 cluster representing the (011) TiO2 surface was conducted and compared to that of CH3COOH on the same cluster. Dissociative adsorptions of both the O-H and C-Br bonds are more stable than the non-dissociative adsorption modes. The di-coordinated species, TiOC(O)CH2Os, formed by the simultaneous dissociation of both C-Br and O-H bonds of BrCH2COOH appears the most plausible surface intermediate for the observed carbon coupling reactions. 相似文献