- Tetrahydro-4 H-pyran-4-one: From the Laboratory Scale to Pilot Plant Manufacture
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This study describes our recent efforts to find an efficient and scalable route to tetrahydro-4H-pyran-4-one using the commercially available starting materials. The route scouting work and the full development of an efficient access to the target are described. This work culminated in the preparation of above 20 kg of the title compound in our pilot plant facility.
- Zahim, Sara,Delacroix, Kenny,Carlier, Agathe,Berranger, Thierry,Bergraser, Julie,Echeverria, Pierre-Georges,Petit, Laurent
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p. 199 - 206
(2022/01/12)
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- Method for synthesizing 1, 3-dihydric alcohol by using olefin and methanol as raw materials
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The invention discloses a method for preparing 1, 3-dihydric alcohol by taking olefin and methanol as raw materials through one-step reaction and a catalyst for the method. The method comprises the following steps: 1) adding a catalyst into a reactor, heating and reducing in a hydrogen-nitrogen mixed atmosphere, then cooling to 60-180 DEG C, and keeping the pressure in the reactor to be 0.5-8 MPa for reaction; 2) respectively introducing olefin and a methanol aqueous solution into the reactor for reaction, wherein the airspeed is 0.01-10h in terms of methanol; 3) enabling that the reaction product enters a product storage tank after condensation and gas-liquid separation; and 4) carrying out rectification separation on the reaction product obtained in the step 3) to obtain a 1, 3-dihydric alcohol product with the purity of more than 99%. The method provided by the invention has the advantages of low raw material cost, simple steps and continuous production.
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Paragraph 0094-0120
(2021/07/28)
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- Zeolite-Catalyzed Formaldehyde–Propylene Prins Condensation
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Prins condensation of formaldehyde with propylene to form 3-buten-1-ol is investigated using microporous solid acid catalysts. Zn/H-beta shows high conversion but leads to a broad product distribution composed primarily of pyrans. Mechanistic studies revealed that 3-buten-1-ol reacts via Prins cyclization or dehydrate to 1,3-butadiene that further reacts with formaldehyde via a hetero-Diels–Alder reaction. These secondary reactions are suppressed over ZSM-5 catalysts: 3-buten-1-ol is the predominant product over H-ZSM-5 zeolite under all conditions investigated. 3-Buten-1-ol selectivity of up to 75 % is achieved. In a second step 3-buten-1-ol dehydrates at temperatures as low as 423 K, forming 1,3-butadiene. Although Br?nsted acid sites are the primary catalytic sites, ion exchange of ZnII increases the overall rate and 3-buten-1-ol selectivity. H-ZSM-5 showed significant differences in reactivity and selectivity as a function of the Si/Al ratio; optimal catalytic properties were observed within Si/Al=40–140.
- Vasiliadou, Efterpi S.,Gould, Nicholas S.,Lobo, Raul F.
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p. 4417 - 4425
(2017/11/20)
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- Rate coefficients for the gas-phase reactions of chlorine atoms with cyclic ethers at 298 K
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Rate coefficients of reactions of Cl atoms with cyclic ethers, tetrahydropyran (THP), tetrahydrofuran (THF), and dihydrofurans (2,5-DHF and 2,3-DHF) have been measured at 298 K using a relative rate method. The relative rate ratios for THP and THF are 0.80 ± 0.05 and 0.80 ± 0.08, respectively, with n-hexane as the reference molecule. The relative rate ratios for THF and 2,5-DHF with n-pentane as the reference molecule are 0.95 ± 0.07 and 1.73 ± 0.06, respectively, and for 2,5-DHF with 1-butene as reference is 1.38 ± 0.05. The average values of the rate coefficients are (2.52 ± 0.36), (2.50 ± 0.39), and (4.48 ± 0.59) × 10-10 cm3 molecule-1 s-1 for THP, THF, and 2,5-DHF, respectively. The errors quoted here for relative rate ratios are 2σ of the statistical variation in different sets of experiments. These errors, combined with the reported errors of the reference rate coefficients using the statistical error propagation equation, are the quoted errors for the rate coefficients. In the case of 2,3-DHF, after correcting for the dark reaction with CH3COCl and assuming no interference from other radical reactions, a relative rate ratio of 0.85 ± 0.16 is obtained with respect to cycloheptene, corresponding to a rate coefficient of (4.52 ± 0.99) × 10-10 cm3 molecule-1 s-1. Unlike cyclic hydrocarbons, there is no increase with increasing number of CH2 groups in these cyclic ethers whereas there is an increase in the rate coefficient with unsaturation in the ring. An attempt is also made to correlate the rate coefficients of cyclic hydrocarbons and ethers with the molecular size as well as HOMO energy.
- Alwe,Walawalkar,Sharma,Pushpa,Dhanya,Naik
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p. 295 - 305
(2013/08/25)
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- Heterogeneous ceria catalyst with water-tolerant Lewis acidic sites for one-pot synthesis of 1,3-diols via prins condensation and hydrolysis reactions
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The use of a heterogeneous Lewis acid catalyst, which is insoluble and easily separable during the reaction, is a promising option for hydrolysis reactions from both environmental and practical viewpoints. In this study, ceria showed excellent catalytic activity in the hydrolysis of 4-methyl-1,3-dioxane to 1,3-butanediol in 95% yield and in the one-pot synthesis of 1,3-butanediol from propylene and formaldehyde via Prins condensation and hydrolysis reactions in an overall yield of 60%. In-depth investigations revealed that ceria is a water-tolerant Lewis acid catalyst, which has seldom been reported previously. The ceria catalysts showed rather unusual high activity in hydrolysis, with a turnover number (TON) of 260, which is rather high for bulk oxide catalysts, whose TONs are usually less than 100. Our conclusion that ceria functions as a Lewis acid catalyst in hydrolysis reactions is firmly supported by thorough characterizations with IR and Raman spectroscopy, acidity measurements with IR and 31P magic-angle-spinning NMR spectroscopy, Na+/H + exchange tests, analyses using the in situ active-site capping method, and isotope-labeling studies. A relationship between surface vacancy sites and catalytic activity has been established. CeO2(111) has been confirmed to be the catalytically active crystalline facet for hydrolysis. Water has been found to be associatively adsorbed on oxygen vacancy sites with medium strength, which does not lead to water dissociation to form stable hydroxides. This explains why the ceria catalyst is water-tolerant.
- Wang, Yehong,Wang, Feng,Song, Qi,Xin, Qin,Xu, Shutao,Xu, Jie
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p. 1506 - 1515
(2013/03/28)
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- Method for producing organic compounds by substituting halogen atoms
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The invention pertains to a method in which a halogen atom of an organic compound is replaced with a group derived from a nucleophilic agent, at high yield and high efficiency, by the following method which includes a step of reacting the nucleophilic agent with an organic material having a halogen atom bonded to a carbon atom having four σ bonds, more specifically: a method for producing an organic compound having Q, the method including a step of reacting a compound represented by general formula (2) with an organic starting material having at least one halogen atom bonded to a carbon atom having four σ bonds so as to replace the halogen atom in the organic starting material with Q:MQa (wherein M represents an alkali metal atom, an alkali earth metal atom, or a rare earth metal atom; Q represents a moiety of an inorganic acid or an active hydrogen compound derived by eliminating a proton, wherein Q is a halogen atom different from the halogen atom in the organic starting material having the halogen atom bonded to the carbon atom having the four σ bonds; and a represents an integer of 1 to 3) in the presence of a compound represented by general formula (1) (wherein Z- represents an anion derived by eliminating a proton from an inorganic acid or an active hydrogen compound; R2 is the same or different; R2 each independently represent a C1-C10 hydrocarbon group or two R2 on the same nitrogen atom may be bonded with each other to form a ring with the nitrogen atom).
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Page 14; 15; 19; 21
(2008/06/13)
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- Regiochemical Control of the Ring Opening of 1,2-Epoxides by Means of Chelating Processes. 6. Opening Reactions of 3,4-Epoxytetrahydropyran
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The regiochemical control of the ring opening of epoxides bearing polar remote functionalities, through chelation processes assisted by metal ions, was verified in the title compound (4).The use of metal assisted procedures in several ring opening reactions of 4 leads to a modification of the regiochemical outcome, and the attack of the nucleophile on the C-4 oxirane carbon is highly favored.
- Chini, Marco,Crotti, Paolo,Gardelli, Cristina,Macchia, Franco
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p. 1261 - 1274
(2007/10/02)
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