- Synthesis and characterization of some bis(hydroxyalkyl)- and bis(hydroxyester)-functionalized disiloxanes
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Novel hydroxyester disiloxanes (1,3-bis(6-hydroxyhexa noylmethyl)-1,1,3,3- tetramethyl disiloxane and 3-bis(2-hydroxypropanoylmethyl)tetramethyl disiloxane) were synthesized, and preparation of other known monomers, namely 1,3-bis(hydroxypropyl)-1,1,3,3-tetramethyl disiloxane, 1,3- bis(hydroxyethoxypropyl)-1,1,3,3-tetramethyl disiloxane and 1,3- bis(hydroxymethyl)-1,1,3,3-tetramethyl disiloxane was developed to obtain better yields and reduce production time and expense. All compounds were characterized by infrared spectroscopy, using 1H NMR, 13C NMR, and 29Si NMR and were reacted with diisocyanates, resulting in poly(siloxane-urethane) copolymers with unique properties.
- Pusztai, Erika,Nagy, Jozsef,Wagner, Oedoen
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- Microwave-assisted synthesis of 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane
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1,3-Bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane was synthesized under microwave irradiation. The structure of the compound was analyzed by infrared spectroscopy, nuclear magnetic resonance hydrogen spectroscopy and gas chromatography. The optimal reaction condition was obtained by the single factor method. Under the optimal condition, the overall yield could reach 83.9 % and the purity of 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane was 99.1 %. It is found that under microwave radiation the reactions are very rapid with good yield, better quality and less time is required for the completion of the reaction.
- Cheng, Xitao,Li, Wenhong,Zhang, Cunshe,Huang, Fangfang,Wang, Qianjin,Zhou, Kui
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- Biocatalytic synthesis of silicone polyesters
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The immobilized lipase B from Candida antarctica (CALB) was used to synthesize silicone polyesters. CALB routinely generated between 74-95% polytransesterification depending on the monomers that were used. Low molecular weight diols resulted in the highes
- Frampton, Mark B.,Subczynska, Izabela,Zelisko, Paul M.
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- Formate dehydrogenase - A biocatalyst with novel applications in organic chemistry
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In the field of industrial biocatalysis, formate dehydrogenase (FDH) is well established, in particular for its broad application in cofactor regeneration. Further applications have been limited by the enzyme's narrow range of substrates. These restrictio
- Froehlich, Peter,Albert, Kristin,Bertau, Martin
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- Synthesis of disiloxanes containing hydroxyalkyl groups
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Four 1,3-bis(ω-hydroxyalkyl)tetramethyldisiloxanes 2O (I; n = 3-6) were synthsized by methanolysis of the correspondig trimethylsilylterminated disiloxanes (III).The latter were obtained from 1,1,3,3-tetramethyldisiloxane (II) and the appropriate (ω-alkenyloxy)trimethylsilanes (IV).Under acidic conditions III formed in addition to I, the corresponding (ω-hydroxyalkyl)pentamethyldisiloxanes HO(CH2)nSiMe2OSiMe3 (V; n = 3-6).
- Braun, F.,Willner, L.,Hess, M.,Kosfeld, R.
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- A dog (d) for the preparation of hexamethyl disilane
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The invention relates to a preparation method for hydroxypropyl (butyl) disiloxane. The preparation method comprises the following steps: (1) mixing an allyl alcohol salt-allyl alcohol mixed solution or an alkenyl butyl alcohol salt-alkenyl butyl alcohol mixed solution and hydrogen chlorosilane in an organic solvent, introducing inert gas, stirring the mixture to react, distilling the mixture and collecting a fraction to obtain an alcoholysis product; (2) adding a hydrosilylation catalyst and a co-catalyst into the alcoholysis product, stirring the mixture to react for 4-10 hours, and after reaction, naturally cooling the mixture to room temperature; and (3) adding a hydrochloric acid solution into the product obtained in the step (2), stirring the mixture and carrying out reflux reaction for 5-12 hours, after reaction, naturally cooling the mixture to room temperature, adjusting the pH to neutral, separating liquids to remove a lower solution, washing an organic phase by water to neutral, extracting the organic phase by an extraction agent, removing the extraction agent and drying the mixture to obtain the hydroxypropyl (butyl) disiloxane. The method provided by the invention is high in yield of target product, the highest yield of the alcoholysis product can reach 94.32%, and the highest yield of an addition-hydrolysate can reach 89.58%.
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Paragraph 0046; 0077; 0078; 0083
(2018/05/30)
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- Method for preparing hydroxyalkyl disiloxane
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The invention relates to a method for preparing hydroxyalkyl disiloxane. The method includes the following steps: (1) mixing carboxylic acid unsaturated ester with dimethylchlorosilane in an organic solvent, introducing inert gas, adding hydrosilyation catalyst and stirring for 2 to 12 hours; (2) dropwising a mixed liquid of acidic aqueous solution and the organic solvent to the hydrosilylation reaction product and hydrolyzing for 1 to 6 hours; (3) regulating the hydrolysis product pH to be neutral, extracting organic layers three times with extraction agent, washing three times, drying for 24 hours and removing the extraction agent by rotary evaporating to obtain the finished product. The method has the advantages of simple operation, simple steps, mild reaction conditions, pure product and high yield, and the yield of the hydrosilylation reaction product can reach 83.2% and the yield of the hydrolysis product can reach 89.5%.
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Paragraph 0049; 0050; 0051; 0055; 0056; 0057
(2017/07/22)
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- Synthesis of polyesters containing disiloxane subunits: Structural characterization, kinetics, and an examination of the thermal tolerance of Novozym-435
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This paper reports the Novozym-435 mediated polymerization of disiloxane-containing polyester monomers under solvent-free conditions. The thermal tolerance of the immobilized enzyme was examined by conducting polymerization cycles over a temperature range of 35-150 °C. Increasing the temperature up to 100 °C afforded an increase in the apparent second order rate constant. Residual activity was measured using the production of octyl palmitate. The enzyme was shown to retain on average greater than 90% of its residual activity regardless of the polymerization temperature. This prompted a study of the long term thermal tolerance of the biocatalyst in which it was determined that over ten reaction cycles there was a significant decrease in the initial polymerization rate, but no change in the degree of monomer conversion after 24 h. The disiloxane containing polyesters were characterized using nuclear magnetic resonance spectroscopy and Fourier-transform infrared spectroscopy. Differential scanning calorimetry was used to determine the thermal properties of the disiloxane-containing polyesters.
- Frampton, Mark B.,Séguin, Jacqueline P.,Marquardt, Drew,Harroun, Thad A.,Zelisko, Paul M.
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p. 149 - 155
(2013/01/15)
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- Initiator-free photocopolymerisation of the hydroxybutylvinyl ether/disiloxane phenylmaleimide system
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The paper deals with the synthesis and characterisation of phenylmaleimide substituted disiloxanes and with their photochemical copolymerisation, in the absence of photoinitiator, with hydroxibutyl vinyl ether. The influence of the ratio between the comonomers, monomer functionality, light intensity and reaction atmosphere on photopolymerisation kinetics was investigated.
- Iojoiu, Cristina,Sava, Miticǎ,Pintealǎ, Mariana,Harabagiu, Valeria,Abadie, Marc J. M.,Simionescu, Bogdan C.,Simionescu, Cristofor I.
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p. 703 - 711
(2007/10/03)
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