Phenylalanine （Phe） is a significant amino acid that cannot be synthesized by human themselves but must be taken from environment. It was initially found that the nanosized amorphous Ni-B/SiO2 alloy prepared by the ...Phenylalanine （Phe） is a significant amino acid that cannot be synthesized by human themselves but must be taken from environment. It was initially found that the nanosized amorphous Ni-B/SiO2 alloy prepared by the chemical reduction method was an effective catalyst for the preparation of Phe from phenylpyruvic acid （PPA） by amination and hydrogenation. It has been found that the amorphous Ni-B/SiO2 alloy catalyst exhibits superior activity and selectivity to the traditional catalysts Raney Ni and Urushibara nickel. The effects of reaction time, amounts of catalysts and ammonia solution, reaction temperature, and H2 pressure on the reaction have been investigated systematically. The results indicated that the yield of Phe was 97.9%, and the selectivity for Phe reached 98.9% when the reaction was carried out for 3 h at 333 K and 2.0 MPa of H2 with m（Cat.） ： m（PPA） = 0.6 ： 1.0 and n（NH3） ： n（PPA） = 3 ： 1. The catalysts were characterized by XRD, AAS, XPS, BET, and TEM, and the relationship between the catalyst structure and the catalytic activity was discussed in detail. It was found that the reason why Ni-B/SiO2 amorphous alloy catalyst was much more active for the preparation of Phe could be accounted for by the presence of electron-rich Ni due to electron donation from alloying B; the smaller size of Ni-B particles, the larger specific surface area of Ni-B/SiO2.展开更多
In this paper,the preparation of phenylpyruvic acid by hydrolysis of 5-benzalhydantoin and its dynamic behavior were studied. The optimized condition of hydrolysis was: reaction in the presence of sodium hydroxide as ...In this paper,the preparation of phenylpyruvic acid by hydrolysis of 5-benzalhydantoin and its dynamic behavior were studied. The optimized condition of hydrolysis was: reaction in the presence of sodium hydroxide as hydrolyte proceeding for two hours at 100?℃.The degradation of 5-benzalhydantoin was close to 100%.展开更多
The complex cobalt pyridine2carboxylate Co(Pyca) 2·4H 2O catalyst is found to have a good activity and selectivity for double carbonylation of benzyl chloride to a substituted phenylpyruvic acid, βbenzyl αpheny...The complex cobalt pyridine2carboxylate Co(Pyca) 2·4H 2O catalyst is found to have a good activity and selectivity for double carbonylation of benzyl chloride to a substituted phenylpyruvic acid, βbenzyl αphenylpyruvic acid, in CaO/CH 3OH/H 2O reaction system. After stirring 10 h in 3.0 MPa and 333 K with the PhCH 2Cl to CaO ratio of 1.33 and catalyst of 5.5 mmol, the yield of the substituted phenylpyruvic acid is 40%, the selectivity is 80%, and the conversion of benzyl chloride is 51%. The substituted phenylpyruvic acid is characterized by IR, NMR, MS and microanalyses. The strong IR bands at 3 453—3 554 cm -1 are assigned to the —COOH , and the sharp bands at 1 706 and 1 729 cm -1 are assigned to the two C=O groups stretch, respectively. In the 13 C NMR spectra, two characteristic strong peaks at δ 1932 and 1592 are assigned to C=O and COOH. The MS spectra shows that the main characteristic peaks are m/z=254(M+), 236, 209, 181(basic peak), 91 and 77. The melting point of the phenylpyruvic acid is 87—89 ℃. Further study of the double carbonylation reaction over this new catalyst system is being carried out.展开更多
基金Fundamental research project of South-Central University for Nationalities (No. YZZ05010)
文摘Phenylalanine （Phe） is a significant amino acid that cannot be synthesized by human themselves but must be taken from environment. It was initially found that the nanosized amorphous Ni-B/SiO2 alloy prepared by the chemical reduction method was an effective catalyst for the preparation of Phe from phenylpyruvic acid （PPA） by amination and hydrogenation. It has been found that the amorphous Ni-B/SiO2 alloy catalyst exhibits superior activity and selectivity to the traditional catalysts Raney Ni and Urushibara nickel. The effects of reaction time, amounts of catalysts and ammonia solution, reaction temperature, and H2 pressure on the reaction have been investigated systematically. The results indicated that the yield of Phe was 97.9%, and the selectivity for Phe reached 98.9% when the reaction was carried out for 3 h at 333 K and 2.0 MPa of H2 with m（Cat.） ： m（PPA） = 0.6 ： 1.0 and n（NH3） ： n（PPA） = 3 ： 1. The catalysts were characterized by XRD, AAS, XPS, BET, and TEM, and the relationship between the catalyst structure and the catalytic activity was discussed in detail. It was found that the reason why Ni-B/SiO2 amorphous alloy catalyst was much more active for the preparation of Phe could be accounted for by the presence of electron-rich Ni due to electron donation from alloying B; the smaller size of Ni-B particles, the larger specific surface area of Ni-B/SiO2.
文摘In this paper,the preparation of phenylpyruvic acid by hydrolysis of 5-benzalhydantoin and its dynamic behavior were studied. The optimized condition of hydrolysis was: reaction in the presence of sodium hydroxide as hydrolyte proceeding for two hours at 100?℃.The degradation of 5-benzalhydantoin was close to 100%.
文摘The complex cobalt pyridine2carboxylate Co(Pyca) 2·4H 2O catalyst is found to have a good activity and selectivity for double carbonylation of benzyl chloride to a substituted phenylpyruvic acid, βbenzyl αphenylpyruvic acid, in CaO/CH 3OH/H 2O reaction system. After stirring 10 h in 3.0 MPa and 333 K with the PhCH 2Cl to CaO ratio of 1.33 and catalyst of 5.5 mmol, the yield of the substituted phenylpyruvic acid is 40%, the selectivity is 80%, and the conversion of benzyl chloride is 51%. The substituted phenylpyruvic acid is characterized by IR, NMR, MS and microanalyses. The strong IR bands at 3 453—3 554 cm -1 are assigned to the —COOH , and the sharp bands at 1 706 and 1 729 cm -1 are assigned to the two C=O groups stretch, respectively. In the 13 C NMR spectra, two characteristic strong peaks at δ 1932 and 1592 are assigned to C=O and COOH. The MS spectra shows that the main characteristic peaks are m/z=254(M+), 236, 209, 181(basic peak), 91 and 77. The melting point of the phenylpyruvic acid is 87—89 ℃. Further study of the double carbonylation reaction over this new catalyst system is being carried out.
