3041-16-5Relevant academic research and scientific papers
Nanotitania catalyzes the chemoselective hydration and alkoxylation of epoxides
Ballesteros–Soberanas, Jordi,Leyva–Pérez, Antonio,Martínez–Castelló, Aarón,Oliver–Meseguer, Judit,Tejeda–Serrano, María
, (2021/10/12)
Glycols and ethoxy– and propoxy–alcohols are fundamental chemicals in industry, with annual productions of millions of tons, still manufactured in many cases with corrosive and unrecoverable catalysts such as KOH, amines and BF3?OEt2. Here we show that commercially available, inexpensive, non–toxic, solid and recyclable nanotitania catalyzes the hydration and alkoxylation of epoxides, with water and primary and secondary alcohols but not with phenols, carboxylic acids and tertiary alcohols. In this way, the chemoselective synthesis of different glycols and 1,4–dioxanones, and the implementation of nanotitania for the production in–flow of glycols and alkoxylated alcohols, has been achieved. Mechanistic studies support the key role of vacancies in the nano–oxide catalyst.
Method for preparing P-dioxanone from diethylene glycol and catalyst thereof
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Paragraph 0047-0075, (2021/05/01)
The invention relates to the technical field of organic catalytic synthesis, in particular to a method for preparing p-dioxanone from diethylene glycol and a catalyst thereof. The method comprise the following steps of reacting the diethylene glycol under the action of the catalyst to generate the p-dioxanone, wherein the catalyst is a supported metal catalyst in which an active metal component is supported on a hydroxyapatite carrier. The method can be carried out in a green solvent or under a solvent-free condition, and p-dioxanone can be prepared from diethylene glycol at a conversion rate of up to 100%; moreover, the reaction process for preparing p-dioxanone from diethylene glycol is simple, the equipment is simple, the operation is simple and convenient, and the reaction conditions are very mild; meanwhile, the preparation process of the catalyst is simple, the cost is low, large-scale production can be realized, the thermal stability of the catalyst is high, and the recycling performance is good; reaction products, catalysts and solvent systems are easy to separate, reaction period is short, and the method is suitable for industrial production.
(Cyclopentadienone)iron-Catalyzed Transfer Dehydrogenation of Symmetrical and Unsymmetrical Diols to Lactones
Tang, Yidan,Meador, Rowan I. L.,Malinchak, Casina T.,Harrison, Emily E.,McCaskey, Kimberly A.,Hempel, Melanie C.,Funk, Timothy W.
, p. 1823 - 1834 (2020/02/04)
Air-stable iron carbonyl compounds bearing cyclopentadienone ligands with varying substitution were explored as catalysts in dehydrogenative diol lactonization reactions using acetone as both the solvent and hydrogen acceptor. Two catalysts with trimethylsilyl groups in the 2- A nd 5-positions, [2,5-(SiMe3)2-3,4-(CH2)4(δ4-C4C= O)]Fe(CO)3 (1) and [2,5-(SiMe3)2-3,4-(CH2)3(δ4-C4C= O)]Fe(CO)3 (2), were found to be the most active, with 2 being the most selective in the lactonization of diols containing both primary and secondary alcohols. Lactones containing five-, six-, and seven-membered rings were successfully synthesized, and no over-oxidations to carboxylic acids were detected. The lactonization of unsymmetrical diols containing two primary alcohols occurred with catalyst 1, but selectivity was low based on alcohol electronics and modest based on alcohol sterics. Evidence for a transfer dehydrogenation mechanism was found, and insight into the origin of selectivity in the lactonization of 1°/2° diols was obtained. Additionally, spectroscopic evidence for a trimethylamine-ligated iron species formed in solution during the reaction was discovered.
Oxidative lactonization of diethylene glycol to high-value-added product 1,4-dioxan-2-one promoted by a highly efficacious and selective catalyst ZnO-ZnCr2O4
Cai, Menglu,Wang, Xiaozhong,Chen, Yingqi,Dai, Liyan
, (2019/09/30)
For the first time, the desired product 1,4-dioxan-2-one (PDO) was successfully synthesized via the oxidative lactonization of diethylene glycol (DEG) under mild conditions. After screening several catalysts (M-Cr-O), we found ZnO-ZnCr2O4 (Zn-Cr-O) catalyst exhibited excellent catalytic performance and this chemical transformation obtained moderate to excellent selectivity (96.22%) and conversion (81.95%) within a 4 h reaction time. Subsequently, the morphology of calcined M-Cr-O was investigated by FT-IR, XRD, FESEM, TEM, and N2 adsorption-desorption tests for further study on catalytic performances. The strength and quantity of acid and base sites over Zn-Cr-O were also detected by NH3-TPD and CO2-TPD, and it was worth noting that the acid/base sites over ZnO-ZnCr2O4 (Zn-Cr-O) catalyst could promote this catalytic process well. Recycle studies demonstrated exceptional stability and recyclability of the prepared catalyst without significant efficiency and selectivity loss after 10 consecutive cycles.
Flavin Nitroalkane Oxidase Mimics Compatibility with NOx/TEMPO Catalysis: Aerobic Oxidization of Alcohols, Diols, and Ethers
Thapa, Pawan,Hazoor, Shan,Chouhan, Bikash,Vuong, Thanh Thuy,Foss, Frank W.
, p. 9096 - 9105 (2020/08/14)
Biomimetic flavin organocatalysts oxidize nitromethane to formaldehyde and NOx - providing a relatively nontoxic, noncaustic, and inexpensive source for catalytic NO2 for aerobic TEMPO oxidations of alcohols, diols, and ethers. Alcohols were oxidized to aldehydes or ketones, cyclic ethers to esters, and terminal diols to lactones. In situ trapping of NOx and formaldehyde suggest an oxidative Nef process reminiscent of flavoprotein nitroalkane oxidase reactivity, which is achieved by relatively stable 1,10-bridged flavins. The metal-free flavin/NOx/TEMPO catalytic cycles are uniquely compatible, especially compared to other Nef and NOx-generating processes, and reveal selectivity over flavin-catalyzed sulfoxide formation. Aliphatic ethers were oxidized by this method, as demonstrated by the conversion of (-)-ambroxide to (+)-sclareolide.
Pd-Catalyzed Aerobic Oxidation Reactions: Strategies to Increase Catalyst Lifetimes
Ho, Wilson C.,Chung, Kevin,Ingram, Andrew J.,Waymouth, Robert M.
supporting information, p. 748 - 757 (2018/01/26)
The palladium complex [(neocuproine)Pd(μ-OAc)]2[OTf]2 (1, neocuproine = 2,9-dimethyl-1,10-phenanthroline) is an effective catalyst precursor for the selective oxidation of primary and secondary alcohols, vicinal diols, polyols, and carbohydrates. Both air and benzoquinone can be used as terminal oxidants, but aerobic oxidations are accompanied by oxidative degradation of the neocuproine ligand, thus necessitating high Pd loadings. Several strategies to improve aerobic catalyst lifetimes were devised, guided by mechanistic studies of catalyst deactivation. These studies implicate a radical autoxidation mechanism initiated by H atom abstraction from the neocuproine ligand. Ligand modifications designed to retard H atom abstractions as well as the addition of sacrificial H atom donors increase catalyst lifetimes and lead to higher turnover numbers (TON) under aerobic conditions. Additional investigations revealed that the addition of benzylic hydroperoxides or styrene leads to significant increases in TON as well. Mechanistic studies suggest that benzylic hydroperoxides function as H atom donors and that styrene is effective at intercepting Pd hydrides. These strategies enabled the selective aerobic oxidation of polyols on preparative scales using as little as 0.25 mol % of Pd, a major improvement over previous work.
Au NPs@ polystyrene resin for mild and selective aerobic oxidation of 1,4 dioxane to 1,4 dioxan-2-ol
Sharma, Anuj S.,Kaur, Harjinder
, p. 56 - 59 (2016/11/30)
Supported gold nanoparticles of sizes 5–8 nm have been found as highly efficient catalyst for the oxidation of 1,4 dioxane, a saturated ether, using elemental oxygen at low temperature. GC–MS analysis of the reaction mixture showed > 85% conversion of 1,4 dioxane with a TON of 1120 h? 1 to 1,4 dioxan-2-ol with 90% selectivity. 1,4 Dioxan-2-one was obtained as the major byproduct along with traces of acetic acid and methoxy dioxalane. The catalyst displayed excellent stability and recyclability. TEM analysis of reused catalyst indicated that there was no significant change in the size, shape and morphology of gold nanoparticles.
Method for producing para-dioxanone using fixed bed reactor
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Paragraph 0026-0027, (2017/04/05)
The present invention relates to a preparation method of para-dioxanone from diethylene glycol using a fixed bed reactor. More particularly, the present invention relates to a preparation method of para-dioxanone by dehydrogenation of diethylene glycol in vapor state in presence of a catalyst inside a fixed bed reactor. The preparation method injects diethylene glycol and hydrogen at the bottom part of a fixed bed reactor in the direction opposite to the gravitational gravity and can maintain high activity of the catalyst for a long period of time. Also, the preparation method of the present invention can have enhanced conversion rate of para-dioxanone, thereby cost-efficiently and effectively preparing para-dioxanone.(AA) GC purity of para-dioxanone(BB) Purity(%)(CC) Control - upper insertion(DD) Test - lower insertion(EE) Period(days)COPYRIGHT KIPO 2016
Efficient and Selective Cu/Nitroxyl-Catalyzed Methods for Aerobic Oxidative Lactonization of Diols
Xie, Xiaomin,Stahl, Shannon S.
supporting information, p. 3767 - 3770 (2015/04/14)
Cu/nitroxyl catalysts have been identified that promote highly efficient and selective aerobic oxidative lactonization of diols under mild reaction conditions using ambient air as the oxidant. The chemo- and regioselectivity of the reaction may be tuned by changing the identity of the nitroxyl cocatalyst. A Cu/ABNO catalyst system (ABNO = 9-azabicyclo[3.3.1]nonan-N-oxyl) shows excellent reactivity with symmetrical diols and hindered unsymmetrical diols, whereas a Cu/TEMPO catalyst system (TEMPO = 2,2,6,6-tetramethyl-1-piperidinyl-N-oxyl) displays excellent chemo- and regioselectivity for the oxidation of less hindered unsymmetrical diols. These catalyst systems are compatible with all classes of alcohols (benzylic, allylic, aliphatic), mediate efficient lactonization of 1,4-, 1,5-, and some 1,6-diols, and tolerate diverse functional groups, including alkenes, heterocycles, and other heteroatom-containing groups.
Chemoselective Pd-catalyzed oxidation of polyols: Synthetic scope and mechanistic studies
Chung, Kevin,Banik, Steven M.,De Crisci, Antonio G.,Pearson, David M.,Blake, Timothy R.,Olsson, Johan V.,Ingram, Andrew J.,Zare, Richard N.,Waymouth, Robert M.
supporting information, p. 7593 - 7602 (2013/07/05)
The regio- and chemoselective oxidation of unprotected vicinal polyols with [(neocuproine)Pd(OAc)]2(OTf)2 (1) (neocuproine = 2,9-dimethyl-1,10-phenanthroline) occurs readily under mild reaction conditions to generate α-hydroxy ketones. The oxidation of vicinal diols is both faster and more selective than the oxidation of primary and secondary alcohols; vicinal 1,2-diols are oxidized selectively to hydroxy ketones, whereas primary alcohols are oxidized in preference to secondary alcohols. Oxidative lactonization of 1,5-diols yields cyclic lactones. Catalyst loadings as low as 0.12 mol % in oxidation reactions on a 10 g scale can be used. The exquisite selectivity of this catalyst system is evident in the chemoselective and stereospecific oxidation of the polyol (S,S)-1,2,3,4-tetrahydroxybutane [(S,S)-threitol] to (S)-erythrulose. Mechanistic, kinetic, and theoretical studies revealed that the rate laws for the oxidation of primary and secondary alcohols differ from those of diols. Density functional theory calculations support the conclusion that β-hydride elimination to give hydroxy ketones is product-determining for the oxidation of vicinal diols, whereas for primary and secondary alcohols, pre-equilibria favoring primary alkoxides are product-determining. In situ desorption electrospray ionization mass spectrometry (DESI-MS) revealed several key intermediates in the proposed catalytic cycle.
