Synthesis Of T Acid And CLT Acid By Liquid Catalytic Hydrogenation

In this paper,the precursor NiAlFeCr alloy powder was prepared by rapid quenching technique.Skeletal Ni modified by Fe and Cr was obtained from the precursor by activation. The precursor NiAlFeCr alloy powder and modified skeletal Ni were characterized by XRD.A reversed phase chromatographic method was developed for the separation of components in the reaction of hydrogenation of nitro T-acid.The mobile phase was methanol/water system with volatile acetic acid and triethylamine.The components were sodium 8-hydroxyaminonaphthalene-1,3,6-trisulfonate,sodium 8-aminonaphthalene-1,3,6-trisulfonate, sodium 8-nitrosonaphthalene-1,3,6-trisulfonate and sodium 8-nitronaphthalene-1,3,6-trisulfonate identified by HPLC/MS,respectively.The modified skeletal Ni was used for liquid phase hydrogenation of nitro T-acid to T-acid. The catalyst showed high activity.Under the conditions:c(nitro T-acid)=0.73mol/L, V(H₂O)=40mL,m(cat.)=0.5g,θ=90℃,p=3.0MPa,time=99min,both the conversion of nitro T-acid and the selectivity of T-acid were 100%,and the average hydrogen adsorption rate was 1.73mmol H₂/min·g,which is higher than commercial skeletal Ni,Mo modified skeletal Ni and self-made Mo modified skeletal Ni.Effect of initial concentration of substrate,amount of catalyst,temperature and pressure were studied.The optimal conditions were:c(nitro T-acid)=0.48～0.97mol/L,m(cat.):m(nitro T-acid)=1:40,θ=90℃,p=3.0MPa.The durability of the catalyst was investigated.The catalyst exhibited excellent stability and per gram catalyst can convert 626g nitro T-acid.The modified skeletal Ni performed high activity and selectivity in hydrogenation of 2-chloro-5-nitrotoluene-4-sulfonic acid to CLT acid.Under the conditions:c(substrate) =0.4mol/L,V(H₂O)=40mL,m(cat.)=0.3g,θ=70℃,p=2.0MPa,time=75min,the conversion of substrate was 99.7%and the selectivity of CLT acid was 97.5%.Effect of reaction conditions was studied and the optimal conditions were:c(substrate) =0.4mol/L,m(cat.):m(substrate)=1:10,θ=70℃,p=2.5MPa.The durability of the catalyst was investigated and catalyst exhibited excellent stability.The catalyst maintained high activity even after 15 times batch-running and the conversion of substrate was higher than 99.2%,the selectivity of CLT acid was higher than 97.0%.