Preparation of Basic Lithium Imidazolium Salt and Their Application for Synthesis of Polycarbonate

Synthesis and properties of bisphenol‐Z polycarbonate via melt transesterification

“…This work chose four different catalysts, namely, Tetrabutyl titanate (TBT), Na 2 CO 3 , NaOH and Li(acac). TBT and NaOH are representative Lewis acid and base catalysts for polycondensation, especially for polyester, and Li(acac) showed good reactivity for BPA and DPC polymerization in the work of Jiang et al 24 …”

“…The whole stage of transesterification reaction is carried out under low pressure in order to remove the by‐product phenol in time. Therefore, it is important to select a suitable vacuum degree during transesterification 24 . As shown in Figure 7, the highest molecular weight polymer was obtained with a vacuum degree of 5000 Pa during transesterification.…”

“…Therefore, it is important to select a suitable vacuum degree during transesterification. 24 As shown in Figure 7, the highest molecular weight polymer was obtained with a vacuum degree of 5000 Pa during transesterification. However, low vacuum will increase the loss of DPC and high vacuum will make phenol difficult to remove, both of which will lead to the low of polymer molecular weight.…”

“…23 This work chose four different catalysts, namely, Tetrabutyl titanate (TBT), Na 2 CO 3 , NaOH and Li(acac). TBT and NaOH are representative Lewis acid and base catalysts for polycondensation, especially for polyester, and Li(acac) showed good reactivity for BPA and DPC polymerization in the work of Jiang et al 24 Table 1 summarizes the results of typical transesterifications catalysts. Catalysts such as TBT and NaOH are effective for the transesterification of BPZ and DPC in the melt, but TBT is not effective for the polycondensation and NaOH has strong alkalinity and high reaction temperature during the condensation stage, which leads to side reactions such as depolymerization and ringopening, affecting polymer molecular weight.…”