采用共沉淀法制备了一系列Ca-Al-LDHs固体碱催化剂用于非均相催化合成2-硝基-2-甲基-1-丙醇。利用XRD、SEM、XPS、CO₂-TPD、FT-IR、BET等分析手段对Ca-Al-LDHs的结构特性、金属价态、碱性强度与催化性能构效关系进行表征,通过2-硝基丙烷与甲醛羟甲基化反应评价了Ca-Al-LDHs固体碱催化剂的催化性能,并对2-硝基-2-甲基-1-丙醇的制备工艺进行了优化。结果表明,所制备的固体碱催化剂表面存在大量强碱性活性位点,并且存在一种新的晶格结构(Ca₁₂Al₁₄O₃₃),该结构的存在提高了该催化剂对羟甲基化反应的催化性能;在温度为70℃、反应时间为2h、n(甲醛)∶n(2-硝基丙烷)=2∶1、m(催化剂)∶m(甲醛)=3∶10的反应条件下,2-硝基丙烷的转化率为96.2%,2-硝基-2-甲基-1-丙醇选择性为99%。催化剂重复使用20次后,产品收率仍能达到60%以上。

A series of Ca-Al-LDHs solid base catalysts are prepared via common precipitation method,and used for heterogeneous catalytic synthesis of 2-nitro-2-methyl-1-propionol.The relationships between the structural characteristics,metal valence state,alkaline intensity respectively and catalytic performance of Ca-Al-LDHs are characterized by means of XRD,SEM,XPS,CO₂-TPD,FT-IR,BET and other measurements.The catalytic performance of Ca-Al-LDHs is evaluated through the hydroxymethylation reaction between 2-nitropropane and formaldehyde,and the preparation process of 2-nitro-2-methyl-1-propane is also optimized.It is shown there is a large amount of strong alkaline activity sites on the surface of the prepared Ca-Al-LDHs.Ca₁₂Al₁₄O₃₃,a new lattice structure,exists and improves the catalytic performance of the catalyst in hydroxymethylation.The conversion rate of 2-nitropropane reaches 96.2%,and the selectivity of 2-nitro-2-methyl-1-propyol reaches 99% when the temperature is 70℃,the reaction lasts for 2 hours,n(formaldehyde)∶n(2-nitratepropionide)=2∶1,and m(catalyst)∶m(formaldehyde)=3∶10.The product yield can still exceed 60% after the catalyst has been reused for 20 times.

贺胜臣(1998-),男,硕士生,研究方向为绿色催化,1046788636@qq.com;楚庆岩(1982-),男,博士,副教授,研究方向为绿色催化,通讯联系人,chuqy@sdut.edu.cn。