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Handbook of Solvents - George Wypych - ChemTech - Ventech!

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820 Maw-Ling Wang<br />

Table 13.3.16. Synthesis <strong>of</strong> aliphatic polysulfide<br />

X in various organic solvent-water system with<br />

DC-18-C-6 catalyst<br />

Solvent Reaction temp. o C Polymer [η], dLg -1 *<br />

CH2Cl2 20 0.30<br />

CHCl3 80 0.31<br />

C6H6 80 0.30<br />

C6H5NO2 80 0.58<br />

CH3CN 80 0.58<br />

None 80 0.73<br />

Data obtained from Imai; 41 Polymerization conditions: 2.5 mmol<br />

<strong>of</strong> VIII and IX, 0.05 mmol <strong>of</strong> DC-18-C-6 in 2.5 mL <strong>of</strong> solvent and<br />

5 mL <strong>of</strong> 1.01 M KOH solution for 48 h, *measured at a concentration<br />

<strong>of</strong> 0.5 gdL -1 in chlor<strong>of</strong>orm at 30 o C<br />

Several polycarbonates 59 were<br />

synthesized by two-phase<br />

polycondensation <strong>of</strong> bisphenols and<br />

brominated with trichloromethyl<br />

chlor<strong>of</strong>ormate in a system <strong>of</strong> an organic<br />

solvent and aqueous alkaline<br />

solution <strong>of</strong> quaternary ammonium<br />

salts. Chlorinated hydrocarbons, dichloromethane<br />

(DCM), tetrachloromethane<br />

(TCM), tetrachloromethane<br />

(TCM) and nitrobenzene (NB)<br />

served as organic solvents. The effects<br />

<strong>of</strong> solvents on the reaction<br />

yields are given in Table 13.3.17. 59<br />

Although polymers with a high yield<br />

were obtained using nitrobenzene<br />

(NB) as an organic solvent, the inherent<br />

viscosities were low.<br />

Polycarbonates were prepared by a<br />

two-phase condensation <strong>of</strong> TCF with bisphenol S. They precipitate from chlorinated hydrocarbon<br />

solvents such as DCM, TCM and DCE. According to both the yield and the inherent<br />

viscosity <strong>of</strong> these polymers, the use <strong>of</strong> BTEAC as a phase-transfer catalyst, sodium hydroxide<br />

as a base and DCE as an organic solvent was suitable to prepare a polycondensate having<br />

a large molar mass and a high yield.<br />

Table 13.3.17 Synthesis <strong>of</strong> bisphenol S-based homopolycarbonate by two-phase<br />

polycondensation catalyzed by PTC a<br />

Reaction conditions Polymer yield<br />

Catalyst % [η], dLg -1 * State<br />

DCM TBAB 76.7 0.21 ppt.<br />

DCM TBAC 76.6 0.10 ppt.<br />

DCM BTEAC 78.7 0.13 ppt.<br />

DCM BTEAB 79.3 0.20 ppt.<br />

TCM TBAB 60.0 0.11 ppt.<br />

TCM BTEAC 83.4 0.12 ppt.<br />

DCE TBAB 88.9 0.28 ppt.<br />

DCE TBAC 76.4 0.12 ppt.<br />

DCE BTEAC 86.5 0.32 ppt.<br />

DCE BTEAB 89.3 0.21 ppt.<br />

NB TBAB 85.0 0.17 solution<br />

NB TBAC 90.6 0.11 solution<br />

Solvent b

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