Studies of the copolymerization of carbon dioxide and cyclohexene oxide with salenal(o-i pr) catalyst and effects of reaction conditions
文献类型：期刊论文
| 作者 | Luo Jianxin1,2; Cui Qi1; Zhang Min1; Liu Baohua1; Chen Liban1 |
| 刊名 | Acta polymerica sinica
 |
| 出版日期 | 2008-05-20 |
| 期号 | 5页码:454-459 |
| 关键词 | Carbon dioxide Cyclohexene oxide Salenal(o-i pr) copolymerization Thermal decomposition |
| ISSN号 | 1000-3304 |
| 通讯作者 | Luo jianxin() |
| 英文摘要 | Salenal (o-i pr) complex, prepared by reaction of salenh(2) (n,n'-bis(salicylidene) -1,2-phenylenediamine) and isopropoxide aluminum, has been shown to be an effective catalyst for the coupling of carbon dioxide and cyclohexene oxide to afford poly(cyclohexenylene carbonate) (pchc) with small quantities of byproduct. the addition of various cocatalysts, including 4-dimethyl (amino) pyridine (dmap), n-methyl imidazole (n-meim), 1,8-diazabicyclo(5.4.0)undec-7-ene (dbu) and tetra-n-butylammonium chloride (bu4ncl) can greatly enhance the catalytic efficiency, and more donating dmap can offer the best copolymerization result. the relative dmap loading also plays an important role in polymer formation. experiments indicated that 1 equiv of dmap was the optimum cocatalyst loading. at higher cocatalyst loading, there is a little increase in polyether linkages as well as a dramatic decrease in the molecular weight of the coplymer. effects of reaction condition such as catalyst concentration, reaction time, temperature, co2 pressure on copoymerization were probed in detail. through varying catalyst concentration, it was found that both lower and higher catalyst concentration led to lower catalytic efficiency and lower m-w, and maximum catalytic efficiency was observed in the presence of catalyst concentration around 2 g/l. the catalyst concentration seemed not to influence the carbonate content in the copolymer significantly. almost in all cases highly alternative copolymers were obtained. as far as reaction time is concerned,the catalytic efficiency and molecular weight are enhanced with increasing time at the beginning, it reaches a maximum around 32 h, and then drops slowly. carbonate content as low as 96.5% was observed at the very beginning, afterward the copolymerization quickly tended to proceed alternatively. both the catalytic efficiency in copolymerization and molecular weight of pchc raised with increasing reaction temperature from 40 degrees c to 800 degrees c. at temperatures above 80 degrees c, the polymer yield and molecular weight went down with further increasing temperature due to serious degradation of the obtained polymer. increasing co2 pressure, while was less than 4 mpa, enhanced the catalytic efficiency. higher pressure favored the formation of alternative copolymer as expected,but rather high co2 pressure was harmful to copolymerization. in conclusion, the best results were obtained from the reaction at 80 degrees c for 32 h, with 2.0 g/l salenal (o-i pr) and co2 pressure of 4 mpa using 1.0 equiv of 4-dimethylaminopyridine (dmap) as cocatalysts. the highest turnover number (ton) is 495 g of polymer/g of catalyst. the produced copolymer is completely alternated polymer (percent of carbonate > 99%), and had a m-n value of 55900 with a polydispersity index of 1.32 as determined by gel permeation chromatography. on c-13-nmr spectroscopy, chemical shifts observerd at 153.7, 153.2, and 153.0 indicate the production of largely atactic polymer. the thermal properties of the copolymer were obtained by means of differential scanning calorimetry (dsc) and thermogravimetric analysis (tga) in n-2 and at a heating rate of 10 k/min. dsc showed that the high alternating pchc copolymer exhibited higher glass transition temperature (136 degrees c) than their corresponding values reported in the literature,and tga results indicated that the high alternating pchc copolymer began its decomposition at 280 degrees c and then decomposed completely upon 350 degrees c. the high alternating pchc has excellent thermal decompose properties. and can be applied as mems sacrificial material. |
| WOS关键词 | METAL-SALEN COMPLEXES ; ALTERNATING COPOLYMERIZATION ; STEREOCHEMISTRY CONTROL ; PROPYLENE-OXIDE ; EPOXIDES ; CO2 ; POLYCARBONATES ; SYSTEM ; SALTS |
| WOS研究方向 | Polymer Science |
| WOS类目 | Polymer Science |
| 语种 | 英语 |
| WOS记录号 | WOS:000256276600010 |
| 出版者 | SCIENCE CHINA PRESS |
| URI标识 | http://www.irgrid.ac.cn/handle/1471x/2388044 |
| 专题 | 中国科学院大学 |
| 通讯作者 | Luo Jianxin |
| 作者单位 | 1.Chinese Acad Sci, Guangzhou Inst Chem, Guangzhou 510650, Peoples R China 2.Chinese Acad Sci, Grad Sch, Beijing 100039, Peoples R China |
| 推荐引用方式 GB/T 7714 | Luo Jianxin,Cui Qi,Zhang Min,et al. Studies of the copolymerization of carbon dioxide and cyclohexene oxide with salenal(o-i pr) catalyst and effects of reaction conditions[J]. Acta polymerica sinica,2008(5):454-459. |
| APA | Luo Jianxin,Cui Qi,Zhang Min,Liu Baohua,&Chen Liban.(2008).Studies of the copolymerization of carbon dioxide and cyclohexene oxide with salenal(o-i pr) catalyst and effects of reaction conditions.Acta polymerica sinica(5),454-459. |
| MLA | Luo Jianxin,et al."Studies of the copolymerization of carbon dioxide and cyclohexene oxide with salenal(o-i pr) catalyst and effects of reaction conditions".Acta polymerica sinica .5(2008):454-459. |
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