- Acetal Metathesis: Mechanistic Insight
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The origins and recent applications of acetal metathesis are discussed in the context of synthesizing polyacetals via acetal metathesis polymerization (AMP). A kinetic study of the acid-catalyzed acetal metathesis reaction suggests the rate = k [H + ][acetal] 2, with MeOCH 2 OMe and EtOCH 2 OEt interchanging to yield MeOCH 2 OEt, achieving the statistical 1:2:1 equilibrium distribution in 4 hours at 80 °C and in 1 hour at 90 °C. Upon heating 1,10-decanediol and diethoxymethane, polydecylene acetal is formed with sequential distillation of ethanol, followed by diethoxymethane. A full mechanism for this polymerization is proposed, which begins with a transacetalization sequence to convert the diol into a bisacetal, followed by acetal metathesis to yield a high-molecular-weight polymer.
- Miller, Stephen A.,Pemba, Alexander G.
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- Tetrachloromethane Hydrodechlorination over Palladium-Containing Nanodiamonds
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Abstract: Using nanodiamonds of the UDD-STP brand 1 wt % palladium-containing nanodiamonds are obtained and tested as catalysts of tetrachloromethane hydrodechlorination under mild conditions (solvents, ethanol and methanol; Т = 298–318 K; PH2 = 0.1 MPa). The catalytic properties of the obtained material and a palladium-containing analog based on activated carbon are compared. It is shown that the hydrodechlorination reaction occurs in a stepwise manner via two pathways: to form products with a smaller content of chlorine, for example, chloroform, and to yield oxygen-containing products, for example, diethyl carbonate. The qualitative and quantitative compositions of reaction products are determined by gas chromatography/mass spectrometry.
- Belkina, E. G.,Gruzdev, M. S.,Kalmykov, P. A.,Klyuev, M. V.,Lysenok, A. A.,Magdalinova, N. A.
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p. 1148 - 1153
(2020/10/14)
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- Method for preparing diethoxymethane by supported heteropolyacid catalyst
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The invention relates to a method for preparing diethoxymethane, in particular to a method for for preparing diethoxymethane by a supported heteropolyacid catalyst. According to the method, dimethoxymethane and ethanol are taken as raw materials, liquid acid and supported liquid acid are taken as catalysts, the preparation method of the supported heteropolyacid catalyst, for example 33% of H3PW12O40/SiO2, comprises the following steps that a phosphotungstic acid aqueous solution with the concentration of 33% by mass is used, SiO2 is taken as a carrier, the impregnation liquid volume is the approximate to the pore volume, a catalyst sample is obtained after the phosphotungstic acid aqueous solution and the SiO2 are mixed uniformly and stood at the normal temperature by 10h, the sample is dried at the temperature of 120 DEG C, and calcination is performed at the temperature of 350 DEG C to obtain the 33% of H3PW12O40/SiO2 catalyst by the mass is prepared. According to the method, the product is relatively simple, the selectivity is high, and the method has an excellent application prospect. The raw materials required by the method are easy to obtain, the whole process operation is simple, at the same time, the method doesn't produce any chemical substances polluting the environment, and the method belongs to the environment-friendly technology route.
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Paragraph 0022; 0023
(2017/03/17)
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- Preparation method of ethoxymethoxy methane
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The invention relates to a method for preparing methane, particularly a method for preparing ethoxymethoxy methane. According to the method, dimethoxymethane and ethanol are used as raw materials to prepare the ethoxymethoxy methane under the conditions of certain temperature and pressure by using a resin as a catalyst. The resin catalyst is one or more of KAD302, KC107, NKC-9, DA-330, D009B, Amberlyst-15 and D072H. The resin catalyst is mainly composed of a sulfo-containing resin catalyst. The reaction temperature is 0-160 DEG C, and the reaction pressure is 0.1-10.0 MPa. The filling gas is inert gas which is argon, helium, carbon dioxide or nitrogen or a gas mixture thereof. The reactor is a fixed-bed or tank reactor. The mole ratio of the raw material dimethoxymethane to the ethanol is 1:2-5:1. The synthesis process has the advantages of simple product, fewer side reactions and high selectivity for the required product ethoxymethoxy methane. The method provided by the invention basically does not pollute the environment.
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Paragraph 0020
(2017/01/02)
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- Method for preparing ethoxy methoxy methane using molecular sieves with different topological structures
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The invention discloses a method for preparing ethoxy methoxy methane using molecular sieves with different topological structures and relates to a method for preparing ethoxy methoxy methane. The ethoxy methoxy methane is prepared by taking dimethoxymethane and ethanol as raw materials and molecular sieves with different topological structures as catalysts at certain temperature and pressure; the silicon-aluminum atom ratio Si/Al in the molecular sieve catalysts with different topological structures is 3-100; the molecular sieves with different topological structures refer to one or more of hydrogen type MCM-22 molecular sieve, hydrogen type ZSM-35 molecular sieve, hydrogen type ZSM-5 molecular sieve, hydrogen type mordenite, hydrogen type Y zeolite and hydrogen type Beta molecular sieve; and the structure types of the molecular sieve catalysts with different topological structures are at least one of MWW, FER, MFI, MOR, FAU and BEA. The method disclosed by the invention has the advantages of relatively single product, high selectivity, cheap and easily available raw materials, easiness in operation of whole process and no production of chemical substances polluting environment and is an environment-friendly technological path.
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Paragraph 0018; 0019; 0020; 0021; 0022; 0023; 0024-0036
(2017/02/28)
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- Method for preparing ethoxy methoxymethane
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The invention provides a method for preparing ethoxy methoxymethane, and relates to a chemical reagent preparation method. According to the method, dimethoxymethane and ethanol serving as raw materials are used to prepare the ethoxy methoxymethane at certain temperature and pressure by using liquid acid and loaded solid acid as catalysts, wherein the liquid acid catalyst is one or more of inorganic acids including sulfuric acid, hydrochloric acid, nitric acid and hydrofluoric acid; the mass percentage of the sulfuric acid catalyst is 0-98 percent, the hydrochloric acid catalyst is an aqueous solution containing hydrogen chloride having a concentration of 0-38 percent, the mass percentage of the nitric acid catalyst is 0-95 percent, and the mass percentage of the hydrofluoric acid catalyst is 0-55 percent; the reaction is performed at the temperature of 0-160 DEG C at a pressure of 0.1-10.0MPa; and the filling gas is one or mixed gas of inert gas, argon, helium, carbon dioxide and nitrogen. The method is relatively single in product and high in selectivity and is prepared from low-price and easily-available raw materials; and the whole process is simple in operation, does not generate chemical substances which pollute the environment, and belongs to an environment-friendly process flow.
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Paragraph 0034; 0035
(2017/01/02)
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- Method for preparing ethoxymethoxy methane by using supported heteropoly acid
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The invention provides a method for preparing ethoxymethoxy methane by using supported heteropoly acid, relating to a method for preparing ethoxymethoxy methane. According to the method, dimethoxymethane and ethanol are used as raw materials to prepare the ethoxymethoxy methane under the conditions of certain temperature and pressure by using supported heteropoly acid as a catalyst. The heteropoly acid catalyst is prepared by an isometric impregnation process by using at least one of activated carbon, TiO2, Al2O3, SiO2, SBA-15 and MCM-41 as a supporter. The supported heteropoly acid catalyst comprises heteropoly acid and a supporter for supporting the heteropoly acid, wherein the heteropoly acid is selected from one or more of phosphotungstic acid, silicotungstic acid, molybdophosphoric acid and silicomolybdic acid. The heteropoly acid accounts for 0.1-50 wt% of the supported heteropoly acid catalyst. The method has the advantages of single product, high selectivity, and cheap and accessible required raw materials, is simple to operate in the whole process, does not generate any environment-hostile chemical substance, and belongs to an environment-friendly technical route.
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Paragraph 0022
(2017/06/24)
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- SYNTHESIS OF UNSYMMETRICAL 1,1-DIALKOXYALKANES AND THEIR SULFUR-CONTAINING ANALOGS
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Acyclic acetals and 1,1-di(alkylthio)alkanes enter into exchange reactions in the presence of aprotic acids and of the KU-2 cation-exchange resin with the formation of the unsymmetric acetals and 1-alkoxy-1-alkylthioalkanes.In reaction with ethylal di(ethylthio)methane forms 3,5,7-trioxanonane in addition to ethylthioethoxymethane. 2-Methyl-4-thia-2-hexene was found in the products from the reaction of 1,1-di(ethylthio)-2-methylpropane with methylal.
- Gazizova, L. B.,Imashev, U. B.,Musavirov, R. S.,Kantor, E. A.,Zlotskii, S. S.,et al.
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p. 226 - 231
(2007/10/02)
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