Reactions of Epoxides in Dimethyl Sulfoxide Catalyzed by Potassium t-Butoxide
Reactions of Epoxides in Dimethyl Sulfoxide Catalyzed by Potassium t-Butoxide
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DOI：
10.1021/ja00969a026
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发表时间：
1966-09
影响因子：
15
通讯作者：
C. Price;Donald D Carmelite
中科院分区：
文献类型：
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作者：
C. Price;Donald D Carmelite
环氧乙烷在DMSO中进行完全聚合，得到分子量由单体与叔丁氧基引发剂之比计算的聚合物。环氧丙烷得到的聚合物的极限分子量约为1200，这受到单体通常的链转移过程的限制。在任何一种情况下，通过红外线都没有观察到可检测的亚砜端基，这表明环氧丙烷的甲基氢比DMSO中的氢更容易被生长的聚合物链上的醇盐基团提取至少1000倍。用氘取代环氧丙烷中的甲基氢，导致分子量增加，烯丙基不饱和度降低，这与涉及该甲基的链转移过程所预期的一样。四甲基环氧乙烷与正丁醇在DMSO中的反应仅通过攻击甲基而进行，以98%产率产生1，1，3-三甲基烯丙醇。三甲基环氧乙烷类似地产生两种异构醇的良好产率，N-二甲基烯丙醇（80%）和N-二甲基烯丙醇（15%）。叔丁基环氧乙烷没有显示出链转移的证据，但与环氧丙烷相比，对聚合的反应性明显更低。由于催化剂在聚合介质中的不溶性，用强碱如KOH进行环氧化物聚合的早期研究2-7涉及到解释问题。这就导致了这样一种说法：（1）从一个博士学位;博士论文由DD卡梅尔，1966年;支持的一部分赠款从通用轮胎和橡胶公司。(2)L. E. St. Pierre和CC Price，J. Am.化学会，78，3432（1956）中所述。(3)E. C，Steiner，R. R. Pelletier和R. O.卡车，同上，86，4678（1964）中所述。
The polymerization of ethylene oxide proceeded to completionin DMSO giving a polymer with a molec-ular weight calculated from the ratio of the monomer to the f-butoxide initiator. Propylene oxide gives a polymer with a limiting molecular weight of about 1200, limited by theusual chain-transfer process to the monomer. No detectable sulfoxide end group was observed by infrared in either case, indicating that the methyl hydrogens of propylene oxide are at least 1000 times more readily abstracted by alkoxide groups on growing polymer chains than are hydrogens in DMSO. Substitution of deuterium for themethyl hydrogens of propylene oxide led to an increase in molecular weight and a decrease in allyl unsaturation, as expected for a chain-transfer process involving this methyl group. The reaction of tetramethylethylene oxide with r-butoxide in DMSO proceeds solely by attack at methyl, producing,,/3-trimethylallyl alcohol in 98% yield. Trimethylethylene oxide similarly produces a good yield of two isomeric alcohols,,-dimethylallyl alcohol (80%) and,/3-dimethylallyl alcohol (15%). z-Butylethylene oxide shows no evidence of chain transfer but is remarkably less reactive to polymerization than propylene oxide. arlier studies of epoxide polymerization by strong bases, such as KOH, 2-7 have involved problems of interpretation due to insolubility of the catalyst in the polymerization medium. This has led to the sug-(1) From a Ph. D. Dissertation by DD Carmelite, 1966; supported in part by a grant from the General Tire and Rubber Co.(2) L. E. St. Pierre and CC Price, J. Am. Chem. Soc., 78, 3432 (1956).(3) E. C, Steiner, R. R. Pelletier, and R. O. Trucks, ibid., 86, 4678 (1964).