2225-98-1Relevant articles and documents
"kick-Starting" oxetane photopolymerizations
Crivello, James V.
, p. 2934 - 2946 (2014)
In the presence of small amounts of 2,2-dialkyl-, 2,2,3-trialkyl-, or 2,2,3,3-tetraalkyl substituted epoxides such as isobutylene oxide, 1,2-limonene oxide, and 2,2,3,3,-tetramethyl oxirane, the photoinitiated cationic ring-opening polymerizations of 3,3-disubstituted oxetanes are dramatically accelerated. The acceleration affect was attributed to an increase in the rate of the initiation step of these latter monomers. Both mono- and disubstituted oxetane monomers are similarly accelerated by the above-mentioned epoxides to give crosslinked network polymers. The potential for the use of such "kick-started" systems in applications such as coatings, adhesives, printing inks, dental composites and in three-dimensional imaging is discussed.
Self-assembled Na12[WZn3(ZnW9O 34)2] as an industrially attractive multi-purpose catalyst for oxidations with aqueous hydrogen peroxide
Witte, Peter T.,Alsters, Paul L.,Jary, Walther,Muellner, Ruth,Poechlauer, Peter,Sloboda-Rozner, Dorit,Neumann, Ronny
, p. 524 - 531 (2004)
Eleven W-based catalyst systems for alkene epoxidation with aqueous H 2O2 were compared under identical conditions and at equal level of 0.1 mol % W-atoms. Of these, those based on a combination of H 2WO4 and a methyltrioctylammonium phase transfer catalyst turned out to be most active in particular systems that contain a source of phosphate. Evidence is presented that under our conditions the actual epoxidizing species in H2WO4-based catalyst systems without phosphate source is mononuclear [WO(OH)(O2)2] - rather than binuclear [{WO(O2)2} 2O]2- that is usually thought to be active. For large-scale applications, however, the polyoxometalate Na12[WZn 3-(ZnW9O34)2] (NaZnPOM) in combination with a suitable phase transfer catalyst such as methyltrioctylammonium chloride is preferred over H2WO 4-based catalysts. This preference results from the fact that use of H2WO4 requires a catalyst activation step that is troublesome on a large scale, whereas epoxidations catalyzed by NaZnPOM start without induction period on addition of H2O2. Optimizations of epoxidations catalyzed by QCl/NaZnPOM or QCl/H 2WO4 have shown that the optimum Q/W ratio depends on the alkene that is epoxidized and differs from that expected from catalyst stoichiometry. An attractive feature of NaZnPOM from the viewpoint of industrial applicability is that epoxidations and other reactions with H2O 2 are efficiently catalyzed by a readily available aqueous solution of NaZnPOM prepared through self-assembly. A 1 mol scale example is provided of an epoxidation catalyzed by a combination of self-assembled NaZnPOM and Luviquat mono CP as a multifunctional cocatalyst with emulsifying, buffering, and phase-transferring properties.
Rational Construction of an Artificial Binuclear Copper Monooxygenase in a Metal-Organic Framework
Feng, Xuanyu,Song, Yang,Chen, Justin S.,Xu, Ziwan,Dunn, Soren J.,Lin, Wenbin
supporting information, p. 1107 - 1118 (2021/01/25)
Artificial enzymatic systems are extensively studied to mimic the structures and functions of their natural counterparts. However, there remains a significant gap between structural modeling and catalytic activity in these artificial systems. Herein we report a novel strategy for the construction of an artificial binuclear copper monooxygenase starting from a Ti metal-organic framework (MOF). The deprotonation of the hydroxide groups on the secondary building units (SBUs) of MIL-125(Ti) (MIL = Matériaux de l'Institut Lavoisier) allows for the metalation of the SBUs with closely spaced CuI pairs, which are oxidized by molecular O2 to afford the CuII2(μ2-OH)2 cofactor in the MOF-based artificial binuclear monooxygenase Ti8-Cu2. An artificial mononuclear Cu monooxygenase Ti8-Cu1 was also prepared for comparison. The MOF-based monooxygenases were characterized by a combination of thermogravimetric analysis, inductively coupled plasma-mass spectrometry, X-ray absorption spectroscopy, Fourier-transform infrared spectroscopy, and UV-vis spectroscopy. In the presence of coreductants, Ti8-Cu2 exhibited outstanding catalytic activity toward a wide range of monooxygenation processes, including epoxidation, hydroxylation, Baeyer-Villiger oxidation, and sulfoxidation, with turnover numbers of up to 3450. Ti8-Cu2 showed a turnover frequency at least 17 times higher than that of Ti8-Cu1. Density functional theory calculations revealed O2 activation as the rate-limiting step in the monooxygenation processes. Computational studies further showed that the Cu2 sites in Ti8-Cu2 cooperatively stabilized the Cu-O2 adduct for O-O bond cleavage with 6.6 kcal/mol smaller free energy increase than that of the mononuclear Cu sites in Ti8-Cu1, accounting for the significantly higher catalytic activity of Ti8-Cu2 over Ti8-Cu1.
Method for preparing 3 - caranol 3 - carene (by machine translation)
-
Paragraph 0012-0013; 0015-0018, (2020/08/27)
A method for preparing 3 - caranol 3 - carene relates to the deep processing of 3 - carene. 3 - Carene, an oxidant and a solvent are mixed, stirred and heated to react, acetic anhydride is added, 3,4 - epoxycarane is obtained after flash distillation, 3,4 - carane of the product 3 - is obtained after rectification and purification. To the method for ring oxidation and hydrogenation ring opening, 3 - carene is converted into 3 - caranol, and meanwhile, the method has higher yield, has a prospect of replacing other terpene alcohol such as terpineol, and can achieve higher economic benefits. (by machine translation)
Oxidative Cleavage of Alkene C=C Bonds Using a Manganese Catalyzed Oxidation with H2O2 Combined with Periodate Oxidation
Mecozzi, Francesco,Dong, Jia Jia,Angelone, Davide,Browne, Wesley R.,Eisink, Niek N. H. M.
supporting information, p. 7151 - 7158 (2019/11/16)
A one-pot multi-step method for the oxidative cleavage of alkenes to aldehydes/ketones under ambient conditions is described as an alternative to ozonolysis. The first step is a highly efficient manganese catalyzed epoxidation/cis-dihydroxylation of alkenes. This step is followed by an Fe(III) assisted ring opening of the epoxide (where necessary) to a 1,2-diol. Carbon–carbon bond cleavage is achieved by treatment of the diol with sodium periodate. The conditions used in each step are not only compatible with the subsequent step(s), but also provide for increased conversion compared to the equivalent reactions carried out on the isolated intermediate compounds. The described procedure allows for carbon–carbon bond cleavage in the presence of other alkenes, oxidation sensitive moieties and other functional groups; the mild conditions (r.t.) used in all three steps make this a viable general alternative to ozonolysis and especially for use under flow or continuous batch conditions.
Optimization of the lipase mediated epoxidation of monoterpenes using the design of experiments—Taguchi method
Ranganathan, Sumanth,Tebbe, Johannes,Wiemann, Lars O.,Sieber, Volker
, p. 1479 - 1485 (2016/10/03)
This work deals with the optimization of the Candida antartica lipase B (CALB) mediated epoxidation of monoterpenes by using the design of experiments (DoE) working with the Taguchi Method. Epoxides are essential organic intermediates that find various industrial applications making the epoxidation one of the most investigated processes in chemical industry. As many as 8 parameters such as the reaction medium, carboxylic acid type, carboxylic acid concentration, temperature, monoterpene type, monoterpene concentration, hydrogen peroxide concentration and amount of lipase were optimized using as less as 18 runs in triplicates (54 runs). As a result, the hydrogen peroxide concentration used was found to be the most influential parameter of this process while the type of monoterpene was least influential. Scaling up of the reaction conditions according to the findings of the optimization achieved full conversion in less than 6?h. In addition, a purification process for the epoxides was developed leading to an isolated yield of ca. 72.3%, 88.8% and 62.5% for α-pinene, 3-carene and limonene, respectively.
An ionic liquid immobilized copper complex for catalytic epoxidation
Dileep,Rudresha
, p. 65870 - 65873 (2015/08/18)
This article brings into focus an in situ strategy of immobilization of a copper complex onto an ionic liquid support. A practical method of olefin and terpene epoxidation by immobilizing a copper complex and 1-ethyl-3-methylimidazolium hexafluorophosphate and using H2O2 as the terminal oxidant is developed. The advantageous properties of this catalytic system redefine an exceptionally clean environment for catalytic epoxidations.
Switching the reaction pathways of electrochemically generated β-haloalkoxysulfonium ions - Synthesis of halohydrins and epoxides
Shimizu, Akihiro,Hayashi, Ryutaro,Ashikari, Yosuke,Nokami, Toshiki,Yoshida, Jun-Ichi
supporting information, p. 242 - 248 (2015/06/01)
β-Haloalkoxysulfonium ions generated by the reaction of electrogenerated Br+ and I+ ions stabilized by dimethyl sulfoxide (DMSO) reacted with sodium hydroxide and sodium methoxide to give the corresponding halohydrins and epoxides, respectively, whereas the treatment with triethylamine gave α-halocarbonyl compounds.
Eco-friendly solvents and amphiphilic catalytic polyoxometalate nanoparticles: A winning combination for olefin epoxidation
Mouret, Adrien,Leclercq, Loic,Muehlbauer, Andrea,Nardello-Rataj, Veronique
, p. 269 - 278 (2014/01/06)
Eighteen eco-friendly solvents were examined to carry out the epoxidation of olefins with the amphiphilic catalytic dodecyltrimethylammonium polyoxometalate nanoparticles [C12]3[PW12O 40] in comparison with [H]3[PW12O40] and [Na]3[PW12O40]. Surprisingly, the screening of solvents with cyclooctene has revealed that the [C 12]3[PW12O40] catalyst is much more active with initial turn-over frequencies, TOF0, increasing up to a factor of 10. Moreover, the reaction occurs at competitive rates in four relevant solvents, i.e. cyclopentyl methyl ether, 2-methyl tetrahydrofuran, methyl acetate and glycerol triacetate, for which TOF0 values are higher than 260 h-1. The recyclability of the systems is demonstrated and the scope of substrates has been successfully extended to cyclohexene, 1-octene, limonene, 3-carene, α-pinene, β-pinene and neryl acetate with good epoxide selectivity. The catalytic performances in the "green" solvent are assigned to the formation of stable [C 12]3[PW12O40] nanoparticle dispersions which have been characterized by transmission electron microscopy and dynamic and multiple light scattering experiments. Finally, the Kamlet-Taft parameters were measured in order to correlate the physicochemical properties of the solvents and the catalytic activity.
Effect of solvents on the rate of epoxidation of α-pinene and Δ3-carene with peroxydecanoic acid
Dutka,Makitra,Dutka,Pal'Chikova,Matsyuk
, p. 298 - 303 (2014/04/17)
Reaction of epoxidation of α-pinene and Δ3-carene with peroxydecanoic acid in various organic solvents was studied. Effective activation energies of oxidation of α-pinene and Δ3- carene with peroxydecanoic acid in various media are evaluated. It is shown that reaction medium significantly affects the rate of the process. Correlation dependences connecting the rate of epoxidation with main parameters of solvents are found.
