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.
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