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2C8H18S*3Cl(1-)*Rh(3+); In ethanol; hexane; at 82℃; for 3h;Heating / reflux; |
This example describes the preparation of 1,3-bis(1,2-epoxy-4-cyclohexylethyl)-1,1,3,3-tetramethyldisiloxane, MEME (I) using RhCl3(SBu2)3 as the hydrosilation catalyst. This reaction was carried out under dry nitrogen, using hot glassware set-up.. A 1-L, 3-necked, round-bottomed flask, equipped with a condenser, addition funnel, and thermometer was charged with 111 g (893 mmol) VCHO under nitrogen flow, followed by 14 microliters of RhCl3(SBu2)3 catalyst solution (3 ppm Rh based on final product weight) and approximately 400 ml hexane.. The addition funnel was charged with MHMH (60 g, 447 mmol) under nitrogen, followed by 10 ml of hexane.. The reaction solution was heated to reflux with stirring, resulting in a solution temperature of 82C. The silane was added dropwise over the course of an hour, resulting in an increase in reflux rate.. The reaction was refluxed for two hours after complete addition of the MHMH, with periodic monitoring of the mixture by infrared spectroscopy.. When the Si-H absorption of MHMH at approximately 2100 cm-1 disappeared, the reaction was judged to be complete.. The solution was cooled to room temperature; the condenser and thermometer were replaced with stopcocks and the addition funnel with a short-path distillation head.. The solution was stripped of volatile components until the vapor temperature was above 50C, and then began to decrease.. The colorless material that remained in the reaction flask weighed 169 g, with manipulative losses accounting for the lost material. |
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platinum(II)Cl2(bis(triphenylphsphine)); In dichloromethane; toluene; at 124 - 126℃; for 4.75h;Heating / reflux; |
Example 1. This example describes the preparation of 1,3-bis(1,2-epoxy-4-cyclohexylethyl)-1,1,3,3-tetramethyldisiloxane, MEME (I) using parts per billion levels of the hydrosilation catalyst, PtCl2(PPh3)2. A 1-liter, 3-necked, round-bottomed flask equipped with a condenser, addition funnel, and thermometer was charged with VCHO (111 g, 893 mmol), followed by 4 microliters of a solution of PtCl2(PPh3)2 in dichloromethane (containing 150 ppb of Pt based on weight of final product) and toluene (150 ml).. The addition funnel was charged with MHMH (60 g, 447 mmol) under nitrogen, followed by toluene (10 ml).. The reaction solution was heated to reflux with stirring, resulting in a solution temperature of 124C. The MHMH solution was then added drop wise over the course of about 45 min, resulting in an increase in reflux rate and solution temperature to 126C. After the addition of the MHMH solution was complete, the reaction mixture was refluxed for about four hours, with periodic testing of the reaction mixture by infrared spectroscopy.. When the peak at approximately 2100 cm-1 disappeared, indicating complete consumption of MHMH, the reaction was judged to be complete.. The solution was cooled to room temperature; the condenser and thermometer were replaced with stopcocks and the addition funnel with a short-path distillation head. The solution was heated with a water bath at 85 C and stripped of volatile components until the vapor temperature was above 70 C. No gel formation was observed during and after the stripping process.. Proton NMR spectrum of the residual material in the reaction flask showed it to be the desired product and free of residual solvent and VCHO. The final product weighed 163.5 g.. Manipulative losses account for the lost material. |
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With sodium hydrogencarbonate;platinum on activated charcoal; In water; at 90℃; for 5h; |
A 100 ml reactor is charged with 66 g (531 mmol=1.05 eq) of VCMX, the required amount of platinum in the form of the Pt on black catalyst 2S, and optionally water and sodium hydrogencarbonate. The reaction mixture is subsequently heated to 90 C. 34 g (506 mmol=1 eq) of M'2 are then run dropwise into the reactor over 5 h. In the course of the synthesis the progress of the reaction is determined by the disappearance of the ?SiH units and the disappearance where appropriate of the epoxy functions, which is monitored by potentiometric assay. When all of the ?SiH units have undergone reaction, the reaction mixture is filtered and then devolatilized for 7 hours under vacuum at a high temperature in the presence or absence of sodium hydrogencarbonate. The viscosity, which is directly correlated with the loss of epoxide functions, is measured before and after devolatilization. The product obtained contains between 85 and 99% of silicone (1) of formula (A) above and of CAS RN 18724.32.-8. |
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