24829-11-6Relevant academic research and scientific papers
One-pot method for preparing diepoxide (by machine translation)
-
Paragraph 0093-0100, (2020/05/01)
The method comprises the following steps, adding a reducing agent water solution :S1. to a reactor: slowly dropwise adding a reducing agent aqueous solution to obtain the diepoxide, adding a reducing agent aqueous solution to the reactor, to obtain the diepoxy, and separating and purifying ;S2. from the organic phase: by one-pot reaction, and adding a reducing agent water, through a pot method to obtain the diepoxide crude solution, to obtain the diepoxide compound. The invention discloses a method for separating and purifying a diepoxide crude product through a high vacuum, distillation . The method comprises the following steps of: adding a reducing agent aqueous solution to the, reactor at a low temperature, to obtain a diepoxide 91% crude, product through 95% a, one-pot reaction, of the diolefin and the m-chloroperoxybenzoic acid solution to obtain a diepoxide crude product solution. (by machine translation)
A surfactant-like ionic liquid with permanganate dissolved as a highly selective epoxidation system
Lu, Yu-Jing,Wong, Wing-Leung,Chow, Cheuk-Fai
, p. 25 - 28 (2015/06/08)
A ligand-free catalytic epoxidation system using permanganate in a surfactant-like ionic liquid (IL) medium was developed. The results indicate that the IL takes crucial effects in the epoxide selectivity. The loading of permanganate is also found critical in preventing over-oxidation of epoxides. The system with 0.3 mol% permanganate and 3.5-equivalent CH3CO3H is able to achieve excellent yields and selectivity of epoxides. The study of epoxidation with KMnO4 in IL medium reveals an unusual oxidation behavior of permanganate not found in traditional solvents.
Manganese acetate in pyrrolidinium ionic liquid as a robust and efficient catalytic system for epoxidation of aliphatic terminal alkenes
Ho, Kam-Piu,Wong, Wing-Leung,Lee, Lawrence Yoon Suk,Lam, Kin-Ming,Chan, Tak Hang,Wong, Kwok-Yin
experimental part, p. 1970 - 1973 (2011/04/15)
Green epoxides! A novel and simple ionic liquid/manganese acetate catalytic system has been developed for the rapid and selective oxidation of aliphatic terminal alkenes to epoxides. It provides an efficient, reusable, and scalable protocol for the green synthesis of epoxides from various aliphatic terminal alkenes.
A simple and effective catalytic system for epoxidation of aliphatic terminal alkenes with manganese(II) as the catalyst
Ho, Kam-Piu,Wong, Wing-Leung,Lam, Kin-Ming,Lai, Cheuk-Piu,Chan, Tak Hang,Wong, Kwok-Yin
experimental part, p. 7988 - 7996 (2009/11/30)
A simple catalytic system that uses commercially available manganese(II) Perchlorate as the catalyst and peracetic acid as the oxidant is found to be very effective in the epoxidation of aliphatic terminal alkenes with high product selectivity at ambient temperature. Many terminal alkenes are epoxidised efficiently on a gram scale in less than an hour to give excellent yields of isolated product (>90%) of epoxides in high purity. Kinetic studies with some C9-alkenes show that the catalytic system is more efficient in epoxidising terminal alkenes than internal alkenes, which is contrary to most commonly known epoxidation systems. The reaction rate for epoxidation decreases in the order: 1-nonene>cis-3-nonene> trans-3-nonene. ESI-MS and EPR spectroscopic studies suggest that the active form of the catalyst is a high-valent oligonuclear manganese species, which probably functions as the oxygen atomtransfer agent in the epoxidation reaction.
Iterative tandem catalysis of secondary diols and diesters to chiral polyesters
Van As, Bart A.C.,Van Buijtenen, Jeroen,Mes, Tristan,Palmans, Anja R.A.,Meijer
, p. 8325 - 8332 (2008/09/16)
The well-known dynamic kinetic resolution of secondary alcohols and esters was extended to secondary diols and diesters to afford chiral polyesters. This process is an example of iterative tandem catalysis (ITC), a polymerization method where the concurrent action of two fundamentally different catalysts is required to achieve chain growth. In order to procure chiral polyesters of high enantiomeric excess value (ee) and good molecular weight, the catalysts employed need to be complementary and compatible during the polymerization reaction. We here show that Shvo's catalyst and Novozym 435 fulfil these requirements. The optimal polymerization conditions of 1,1′-(1,3-phenylene) diethanol (1,3-diol) and diisopropyl adipate required 2mol% Shvo's catalyst and 12 mg Novozym 435 per mmol alcohol group in the presence of 0.5 M 2,4-dimethyl-3- pentanol as the hydrogen donor. With these conditions, chiral polyesters were obtained with peak molecular weights up to 15kDa, an ee value up to 99% and with 1-3% ketone end groups. Also with the structural isomer, 1,4-diol, a chiral polyester was obtained, albeit with lower molecular weight (8.3 kDa) and slightly lower ee (94%). Aliphatic secondary diols also resulted in enantio-enriched polymers but at most an ee of 46% was obtained with molecular weights in the range of 3.33.7 kDa. This low ee originates from the intrinsic low enantioselectivity of Novozym 435 for this type of secondary aliphatic diols. The results presented here show that ITC can be applied to procure chiral polyesters with good molecular weight and high ee from optically inactive AA-BB type monomers.
Hydrolytic kinetic resolution of terminal mono- and bis-epoxides in the synthesis of insect pheromones
Chow, Sharon,Kitching, William
, p. 779 - 793 (2007/10/03)
Hydrolytic kinetic resolution (HKR) of functionalised epoxides using (salen)Co(OAc) complexes provides enantiomerically enriched epoxides and diols, which have been transformed into important insect sex pheromones. In this general approach, (-)-(R)- and (+)-(S)-10-methyldodecyl acetates from the smaller tea tortrix moth were obtained, as was (-)-(R)-10-methyltridecan-2-one from the southern corn rootworm. The (S)-epoxide obtained from undec-1-en-6-yne was transformed to (-)-(R)-(Z)-undec-6-en-2-ol (Nostrenol) from ant-lions. HKR of appropriate bisepoxides was also investigated, and transformations of the resulting bisepoxides and epoxydiols provided (-)-(1R,7R)-1,7-dimethylnonylpropanoate from corn rootworms, (-)-(6R,12R)-6,12-dimethylpentadecan-2-one from the female banded cucumber beetle, and (-)-(2S,11S)-2,11-diacetoxytridecane and (+)-(2S,12S)-2,12-diacetoxytridecane from female pea-midges.
