497-26-7Relevant articles and documents
Degradation in Order: Simple and Versatile One-Pot Combination of Two Macromolecular Concepts to Encode Diverse and Spatially Regulated Degradability Functions
Fuoco, Tiziana
, p. 15482 - 15489 (2021)
The clever one-pot combination of two macromolecular concepts, ring-opening polymerization (ROP) and step-growth polymerization (SGP), is demonstrated to be a simple, yet powerful tool to design a library of sequence-controlled polymers with diverse and spatially regulated degradability functions. ROP and SGP occur sequentially at room temperature when the organocatalytic conditions are switched from basic to acidic, and each allows the encoding of specific degradable bonds. ROP controls the sequence length and position of the degradability functions, while SGP between the complementary vinyl ether and hydroxyl chain-ends enables the formation of acetal bonds and high-molar-mass copolymers. The result is the rational combination of cleavable bonds prone to either bulk or surface erosion within the same macromolecule. The strategy is versatile and offers higher chemical diversity and level of control over the primary structure than current aliphatic polyesters or polycarbonates, while being simple, effective, and atom-economical and having potential for scalability.
Liquid-phase Oxidation of 1,2-Ethane Diol
Schnurpfeil, D.,Maurer, G.
, p. 307 - 310 (1994)
The oxidation rate and the kind of oxidation products in the reaction of 1,2-ethane diol (1) with molecular oxygen in liquid phase at 150 deg C were investigated. 1 has a very low oxidation rate.Cu-, Zn-, Fe-, Co- and Al-acetylacetonates as catalysts increase the reaction rate.The main-products of the investigated reaction are the 1,3-dioxolan (2), the 2-methyl-1,3-dioxolan (3) and the 2-methylol-1,3-dioxolan (4).The formation of formic and acetic acids and of the 1,3-dioxolanes is proved by GC, DC and HPLC.
Synthesis of ZSM-22 and Testing Its Catalytic Properties in the Ethylene Oxide Isomerization Reaction
Lazareva,Piryutko,Chernyavskii,Kharitonov
, p. 910 - 917 (2019)
Abstract: The influence of the key parameters of the synthesis of a TON-type zeolite (ZSM-22) with or without an organic structure-directing agent on its phase composition has been established. The optimal composition of the reaction mixture and the crystallization time of ZSM-22 in the presence of 1,6-diaminohexane under static conditions have been determined. The dynamics of the formation of an impurity ZSM-5 by cocrystallization during the synthesis with stirring has been revealed. For zeolite ZSM-22 synthesized using the template-free procedure, the most important factors affecting the crystallinity and the crystallization time are the synthesis temperature, the amount of seed, and agitation of the reaction mixture. The zeolites synthesized according to the both procedures have been examined in the reaction of isomerization of ethylene oxide to acetaldehyde. Zeolite ZSM-22 obtained without adding the template is not inferior in activity to the zeolite of the same structure prepared in the presence of 1,6-diaminohexane. Moreover, it exhibits higher selectivity of ethylene oxide conversion to acetaldehyde. The complete conversion of ethylene oxide has been observed on ZSM-22 zeolites of both types at a reaction temperature of 400°C, the selectivity of its conversion to acetaldehyde being at least 93%.
Catalysis, kinetic and mechanistical studies for the transformation of ethylene glycol by alumina and silica gel under autogenous pressure and solvent-free conditions
Rohand, Taoufik,Tanemura, Kiyoshi
, p. 387 - 394 (2021/06/25)
A kinetic and mechanistical studies of the new pathway for competitive transformation of ethylene glycol by alumina and silica gel have been described. Commercial alumina (Al com), synthetic alumina (Al syn), commercial silica gel (Si com) and synthetic silica gel (Si syn) were used for the transformation of ethylene glycol to a mixture of diethylene glycol, 1,4-dioxane and 2-methyl-1,3-dioxolane via acetaldehyde by heating at 150 °C under autogenous pressure without solvent. The results show that the yield of these three products strongly depends on the nature of the used catalyst and the reaction time.
Photocatalytic Synthesis of 1,3-Dioxacyclanes from Diols and Primary Alcohols Effected by a System FeCl3–NaNO2/O2(Air)
Makhmutov
, p. 1710 - 1714 (2019/02/14)
Diols and primary alcohols were subjected to the action of a system FeCl3–NaNO2/O2 (air) under mercury lamp irradiation to synthesize unsubstituted and 2-methyl-1,3-dioxacyclanes: 1,3-dioxolane, 1,3-dioxepane, 1,3-dioxocane, 2-methyl-1,3-dioxolane, 2-methyl-1,3-dioxepane, 2-methyl-1,3-dioxocane. The probable mechanism of the photocatalytic synthesis of 1,3-dioxacyclanes was described by an example of 2-methyl-1,3-dioxolane.
Synthesis of dioxolanes and oxazolidines by silica gel catalysis
Rohand, Taoufik,Savary, Jér?me,Markó, István E.
, p. 1429 - 1436 (2018/06/25)
Abstract: Ethylene glycol condensed with carbonyl compounds in the presence of silica gel or alumina, without solvent and under pressure, affords 1,3-dioxolanes. 2-Amino-2-methylpropanol also condensed with carbonyl compounds in the presence of silica gel or an acid-activated clay, without solvent and under pressure, produces oxazolidines. To explain these results, we propose that the glycol and the aminopropanol react with Br?nsted (H+) and Lewis acid sites (Si and Al) located on the surface of the catalysts, leading to the products via various ionic intermediates.
Preparation method of cyclic acetal
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Paragraph 0035; 0036; 0037; 0038, (2017/08/29)
The invention discloses a preparation method of cyclic acetal. The method is characterized in that long-chain polyhydroxy compounds and small-molecular aldehydes are used as the substrates, long-chain weak-polarity molecules are used as the solvent, and the aldehydes are condensed with the hydroxyl groups at two ends of the polyhydroxy compounds under the effect of a catalyst to form the intramolecular cyclic acetal. Compared with a traditional acetal preparation method, the method has the advantages that the property differences of the solvent, reactants and the substrates are utilized to allow the aldehydes to be easy to react with the hydroxyl groups, and the cyclic acetal proportion in the product is high; the conversion rate of the aldehyde compounds reaches above 80%, and the selectivity of the cyclic acetal can reach above 80%.
METHOD OF MANUFACTURING 2-METHYL-1,3-DIOXOLANE IN A SOLID STATE POLYCONDENSATION PROCESS
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Paragraph 13; 14, (2017/06/02)
The invention relates to a method for producing 2-methyl-1,3-dioxolane from a polyester solid state polymerization system. The method comprises using an acid catalyst to effectuate the conversion of acetaldehyde present within the system to 2-methyl-1,3-dioxolane, which can be readily removed in the ethylene glycol stream.
Production of aldehydes from 1,2-alkanediols over silica-supported WO3 catalyst
Sun, Daolai,Yamada, Yasuhiro,Sato, Satoshi,Suganuma, Satoshi,Katada, Naonobu
, p. 164 - 171 (2016/09/09)
Vapor-phase dehydration of several 1,2-alkanediols, such as 1,2-ethanediol, 1,2-propanediol, 1,2-butanediol and 1,2-pentanediol, to produce corresponding aldehydes was investigated over silica-supported WO3 catalyst, which was prepared by impregnation method and then calcined at 320?°C. Higher than 90% yield of aldehydes could be achieved over WO3/SiO2 catalyst at 250?°C with a feed of 20% aqueous 1,2-alkanediol solution. Both Br?nsted and Lewis acid sites exist on WO3/SiO2 catalyst, while Br?nsted acid sites are proposed to be the active species for the formation of aldehyde. High concentrations of H2O were effective for inhibiting the intermolecular reaction and improving the selectivity to aldehydes. The dehydration of different 1,2-alkanediols was compared under different reaction conditions. The reactivity of 1,2-ethanediol was low and the product distribution was several comparing with those of the other 1,2-alkanediols. Cyclic acetal, which was generated by the cyclodehydration of the produced aldehyde with another 1,2-alkanediol, was a main by-product, and the formation of acetal was affected by both the temperature and the carbon-chain length of the 1,2-alkanediols.
METHOD OF MANUFACTURING 2-METHYL-1, 3-DIOXOLANE IN A SOLID STATE POLYCONDENSATION PROCESS
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Page/Page column 11; 12, (2015/07/07)
The invention relates to a method for producing 2-methyl-1,3-dioxolane from a polyester solid state polymerization system. The method comprises using an acid catalyst to effectuate the conversion of acetaldehyde present within the system to 2-methyl-1,3-dioxolane, which can be readily removed in the ethylene glycol stream.
