A two-step solvothermal procedure to improve crystallinity of covalent organic frameworks and achieve scale-up preparation

Covalent organic frameworks(COFs),as a novel class of functional polymers,exhibit versatile applica-tions due to their crystalline porous structures and conjugated skeletons.However,synthesis of COFs with high crystallinity still faces great challenges,especially for scale-up preparation.Herein we report a two-step solvothermal process to improve crystallinity of COFs.The first step focuses on polycondensa-tion of monomers with no need for optimizing crystallization conditions.In the second step,appropriate solvothermal conditions are used to facilitate crystallization of the COFs through defects correction and structural repairing.Furthermore,this strategy could also be applicable to scale-up synthesis of high qual-ity COFs,which lays a foundation for their practical applications.

氯化胆碱-尿素低共熔溶剂公斤级放大制备研究

研究了氯化胆碱-尿素低共熔溶剂DES的公斤级放大制备规律。考察了物料配比、反应时间及反应温度对最终产品DES理化性质的影响,分别测定了合成过程中DES折光率、电导率和粘度等性质指标的变化,并通过FT-IR红外光谱分析了DES产品可能的化学结构。实验结果表明,在氯化胆碱与尿素的比例为1∶1时,不能生成DES;氯化胆碱与尿素比例为1∶1.5和1∶2时,均可生成DES;在比例为1∶2的条件下,60℃时不能生成DES,70、80和90℃时均可生成DES,且生成DES的时间随温度的升高而缩短。当DES折光率达到0.6时,其性质趋于稳定,可认为形成了结构稳定的DES。此外还发现,原料和产品中的水含量对DES产品的理化性质有一定程度的影响。本研究澄清了文献报道的DES理化性质存在差异的原因,为工业化放大生产氯化胆碱-尿素DES提供了基础数据。

千克级非布司他晶型A制备工艺

通过晶型转化试验研究了非布司他晶型A实验室及千克级放大制备方法。用正交试验考察了溶剂种类、溶剂用量、溶解温度、析晶温度、析晶时间等因素对非布司他晶型形成和收率的影响。优化工艺为:在75℃条件下,非布司他溶解于8倍量(w/v)的无水乙醇中,10 min后缓慢(0.5~1.0℃/min)冷却至10℃,低速(100 r/min以下)搅拌析晶4 h,收率93%~96%,溶剂可循环利用2次。本工艺制备非布司他晶型A操作简单、安全环保、析晶时间短,有利于工业化。