Aluminum Schiff Base Catalyst for Ring-opening Polymerization of ε-Caprolactone†

doi:10.7503/cjcu20130959

Abstract

Abstract:

The catalysts with high activity and low toxicity for ring opening polymerization(ROP) of ε-caprolactone had drawn much attention both in academia and industry. A series of asymmetric Schiff base aluminum complexes containing ligands that differed in their steric properties were synthesized. Their catalytic properties in the solution polymerization of ε-CL were examined. The kinetics studies of all complexes/2-propanol indicated that all of polymerizations were first-ordered reaction to monomers, and the polymerization rate of electrophilic substituted complex was about 4 times the non-electrophilic substituted complex in ROP of ε-CL. The results evaluated that the electrophilic substituent of ligands has great influence on the catalytic activity of the complex.

Key words: ε-Caprolactone, Ring-opening polymerization, Schiff base aluminun catalyst

CLC Number:

O631

TrendMD:

QU Zhi, LI Xiang, PANG Xuan, DUAN Ranlong, GAO Bo, CHEN Xuesi. Aluminum Schiff Base Catalyst for Ring-opening Polymerization of ε-Caprolactone^†[J]. Chem. J. Chinese Universities, 2014, 35(4): 869.

Figures/Tables 6

Scheme 1 Synthesis of ligands and complexes

Table 1 Polymerization data of ε-CL using complexes 1a—3a*

Complex	Temperature/℃	Time/h	Conv.(¹H NMR)(%)	10^-3 M_n(GPC)	PDI(GPC)
1a	40	20	99	18.4	1.23
1a	60	10	99	23.4	1.35
1a	80	5	99	22.6	1.47
2a	40	20	99	21.5	1.19
2a	60	10	99	21.7	1.31
2a	80	5	99	24.8	1.39
3a	40	20	99	22.6	1.25
3a	60	10	100	23.4	1.28
3a	80	5	100	25.7	1.43

Fig.1 1H NMR spectrum of PCL

Fig.2 First-order kinetics plots for the ROP of ε-CL with 1a/2-propanol as catalyst/initiator in toluene with 60 ℃ and [CL]0=0.5 mol/L for [CL]/[Cat]=100:1(a) and 200:1(b)

Fig.3 First-order kinetics plots for the ROP of ε-CL with 3a/2-propanol as catalyst/initiator in toluene with [CL]0=0.5 mol/L, [CL]/[Cat]=200:1 at 40 ℃(a) and 60 ℃(b)

Fig.4 First-order kinetics plots for the ROP of ε-CL with 1a,3a/2-propanol as catalyst/initiator in toluene with 60 ℃, [CL]0=0.5 mol/L, [CL]/[Cat]=200:1 for 1a(a), 2a(b) and 3a(c)

References 26

[1]	Okada M., Progress in Polymer Science, 2002, 27, 87—133
[2]	Wu J. C., Yu T. L., Chen C. T., Lin C. C., Coordination Chemistry Reviews,2006, 250, 602—626
[3]	Albertsson A. C., Varma I. K., Biomacromolecules,2003, 4, 1466—1486
[4]	Dai W. F, Du. Z. Z., He Y. Y, Lang M. D., Chem. J. Chinese Universities,2009, 30(10), 2076—2081
	(戴炜枫, 杜征臻, 何月英, 郎美东.高等学校化学学报, 2009, 30(10), 2076—2081)
[5]	Malcolm H.C., Huffman J. C., Khamphee P., J. Chem. Soc.,Dalton Trans., 2001, 222—224
[6]	Zhong Z. Y., Dijkstra P. J., Birg C., Westerhausen M., Feijen J., Macromolecules,2001, 34, 3863—3868
[7]	Chisholm M. H., Navarro-Llobet D., Simonsick W. J., Macromolecules,2001, 34, 8851—8857
[8]	Antelmann B., Chisholm M. H., Iyer S. S., Huffman J. C., Navarro-Llobet D., Pagel M., Simonsick W. J., Zhong W. Q., Macromolecules,2001, 34, 3159—3175
[9]	Chakraborty D., Chen E., Macromolecules,2002, 35, 13—15
[10]	Yu R. C., Hung C. H., Huang J. H., Lee H. Y., Chen J. T., Inorg. Chem., 2002, 41, 6450—6455
[11]	Dagorne S., Lavanant L., Welter R., Chassenieux C., Haquette P., Jaouen G., Organometallics,2003, 22, 3732—3741
[12]	Takashima Y., Nakayama Y., Hirao T., Yasuda H., Harada A., Journal of Organometallic Chemistry,2004, 689, 612—619
[13]	Cayuela J., Bounor L. V., Cassagnau P., Michel A., Macromolecules,2006, 39, 1338—1346
[14]	Chmura A. J., Davidson M. G., Jones M. D., Lunn M. D., Mahon M. F., Johnson A. F., Khunkamchoo P., Roberts S. L., Wong S. S. F., Macromolecules,2006, 39, 7250—7257
[15]	O'Keefe B. J., Breyfogle L. E., Hillmyer M. A., Tolman W. B., J. Am. Chem. Soc., 2002, 124, 4384—4393
[16]	Walker D. A., Woodman T. J., Schormann M., Hughes D. L., Bochmann M., Organometallics,2003, 22, 797—803
[17]	Sarazin Y., Schormann M., Bochmann M., Organometallics,2004, 23, 3296—3302
[18]	Deshayes G. Frédéric A. G, Degée P., Verbruggen I., Biesemans M., Willem R., Dubois P., Chemistry: A European Journal,2003, 9, 4346—4352
[19]	Kowalski A., Duda A., Penczek S., Macromolecules,2000, 33, 689—695
[20]	Delbridge E.E., Nelson C. R., Skelton B. W., White A. H.,Dalton Trans., 2007, 143—153
[21]	Zhu W. P., Tong X. W., Shen Z. Q., Chem. J. Chinese Universities,2007, 28(6), 1186—1188
	(朱蔚璞, 童晓薇, 沈之荃. 高等学校化学学报, 2007, 28(6), 1186—1188)
[22]	Chen L., Chen X. S., Deng M. X., Jing X. B., Chem. Res. Chinese Universities,2005, 21(3), 340—344
[23]	Nomura N., Aoyama T., Ishii R., Kondo T., Macromolecules,2005, 38(13), 5363—5366
[24]	Benn R., Runska A., Lehmkuhl H., Janssen E., Kruger C., Angew.Chem. Int.Ed.Eng., 1983, 22, 779—780
[25]	Qu Z., Li X., Pang X., Duan R. L., Gao B., Chen X. S., Chem. J. Chinese Universities,2014, 35(3), 626—632
	(曲智, 李想, 庞烜, 段然龙, 高波, 陈学思. 高等学校化学学报, 2014, 35(3), 626—632)
[26]	Pang X., Du H. Z., Chen X. S., Wang X. H., Jing X. B., Chemistry: A European Journal,2008, 14, 3126—3136