Preparation, Characterization and Application of ZnAlLa-Hydrotalcite-Like Compounds

The preparation of ZnAlLa-hydrotalcite-like compounds [ZnAlLa-HTLcs] was studied.ZnAlLa-HTLcs were synthesized by a method of variable pH with the raw materials of Zn(NO3)2.Al(NO3)3, La(NO3)3, and NaOH. The effects of some factors (i.e. pH values, the mole ratio of Al^3- to La^3-.temperature and the period of hydrothermal treatment) on the preparation of HTLcs were discussed systematically. XRD. TG-DTA. FT-IR spectroscopy, and ICP were performed to characterize ZnAlLa-HTLcs samples, and the thermal stability of HTLcs was also discussed. It was shown that unique ZnAlLa-HTLcs with high crystallinity can be prepared, under the conditions of pH=5.5-6.5. n(Zn^2 )/n(Al^3 La^3 )=2 and the atomic ratio of La^3 to Al^3 ranging from 0.07 to 2. hydrothermal treatment at 120℃ for 5 h. When the calcination of the HTLcs is performed at temperatures above 200℃. ZnO phase is detected with Al2O3 and La2O3 spreading on its top. The complex metal oxides derived from ZnAlLa-HTLcs at 500℃ have higher catalytic activity and selectivity than those from ZnAl-HTLcs for the esterification of acetic acid with n-butanol under the same reaction conditions.     

The Reaction of N-Phenyliminoketenylidenetriphenyl-phosphorane with α,β-Unsaturated Carbonyl Compounds. Synthesis of New Pyran Derivatives

Abstract

The reaction of N-phenyliminoketenylidenetriphenylphosphorane [a] (1), with 2-benzylidene-1, 3-indandione (2), 1,2-diphenyl-3,4-pyrazolidenedione (3)and/or 5-benzylidene barbituric acid (4) has been investigated. When ylide 1 was allowed to react with compounds 2, 3 or 4 in THF at ambient temp. the corresponding new pyrano-phosphoranylidenes 5, 6 or 7 were obtained. The elemental microanalyses, IR, ¹H NMR, ³¹P NMR and MS data agree with the structure of the cyclic iminophosphoranes by [4+2]-cycloaddition and exclude 4-membered ring structure by [2+2]-cycloaddition. When the Wittig reaction was carried on the pyrano-phosphoranes 5, 6 or 7 using p-nitrobenzaldehyde, the exocyclic olefins together with triphenylphosphine oxide were isolated.     

Preparation, Characterization, and Catalytical Application of MgCoAl-Hydrotalcite-Like Compounds

MgCoAl-hydrotalcite-like compounds(MgCoAl-HTLcs)were synthesized using the copre- cipitation method of variable pH values.The effect of each factor on the preparation of HTLcs was discussed systematically,which included pH values,mole ratios of Mg~(2 )to Co~(2 ),the concentrations of the solution,and the temperature and time of the hydrothermal treatment.Besides.the thermal de- composition of MgCoAl-HTLcs was discussed.X-ray diffraction,thermogravimetric analysis,and FT-IR spectroscopy were performed to characterize the MgCoAl-HTLcs samples.The results showed that when the pH=7.6-8.5 or 5.5-6.2,atomic ratios of(Mg~(2 ) Co~(2 ))/Al~(3 )=2 and Mg~(2 )/Co~(2 )ranging from 1.00 to 2.00,temperature and time of hydrothermal treatment being 110℃and 6 h,unique MgCoAl-HTLcs with high crystallinity could be obtained.When the calcination temperature was up to 250℃,the MgO phase was detected coexisting with Al_2O_3 and MgAl_2O_4 was highly spreaded on the derived mixed oxides. The synthesis reaction of benzoin methyl ether with methanol and benzaldehyde was chosen to study the catalytic activity of MgCoAl-HTLcs.The catalyst showed high activity and high stability in the synthesis of benzoin methyl ether in the feasible condition.     

Reactions of Aromatic Nitro Compounds: LXXIV. Azo Coupling of Anionic Nitroarene σ-Complexes with Aromatic Diazo Compounds. Effect of Reaction Conditions on the Yield of Nitroazobenzenes

Effect of a number of factors on the yield of nitroazobenzenes in the reaction of 4-nitro- and 4-dimethylaminobenzenediazonium tetrafluoroborates with anionic adducts derived from 1,3-dinitrobenzene was studied. Conditions were found which allow nitroazobenzenes to be prepared in 80-90% yield.     

Synthesis of Related Compounds of Carotenoid

类胡萝卜素是一类奇特的色素，由高等植物和微生物光化学合成，作为防止单线氧通过光敏反应产生危害的必要基团，类胡萝卜素最近受到了关注。类胡萝卜素联于富勒烯上，既可大大增加在可见光区域光诱导电子转移的有效吸收断面，又可抑制富勒烯敏化单线氧的危害能力。合成了类胡萝卜素的相关化合物，报道的某些反应条件先进且简洁。     

Selective Phosphorylation of α,β-Unsaturated Carbonyl Compounds

Abstract

Elaboration of effective methods of selective phosphorylation of α,β-unsaturated carbonyl compounds containing simultaneously C[dbnd]C and C[dbnd]O bonds, which may compete with each other or react consistently one after another, is one of the most complex problems in the modern organophosphorus synthesis. On the basis of our previous systematic investigations of kinetics and mechanism of the Pudovik and Abramov reactions in the series of α,β-unsaturated carbonyl compounds we have suggested three possible ways to solve this problem: a) soft reaction conditions, regulated by solvent, catalyst and temperature; b) interface catalysis; c) metallocomlex catalysis (reaction in the coordination sphere of transition metal).     

Phosphorylated,Silylated, and Stannylated Derivatives of α-Mercaptocarbonyl Compounds

The authors are summing up their research in the field of phosphorylation, silylation, and stannylation of -mercaptocarbonyl compounds. Synthetic methods were developed for a series of new saturated and unsaturated organosilicon(tin) reagents that were applied to organophosphorus syntheses. Representatives of new classes of heterocyclic compounds were prepared: 1,3,2-oxathiaphospholenes with four- and five-coordinate phosphorus. A new thiophosphite-thiophosphate rearrangement initiated by molecular oxygen was discovered.     

Reactivity of α,α-Dihalogenated Imino Compounds. Part VIII1. Aziridine Formation by Lithium Aluminium Hydride Reduction of N-2-(1,1-Dichloroalkylidene) Cyclohexylamines

1,2-Disubstituted aziridines 2 are not readily accessible and most syntheses remain laborious³. We recently reported⁴ that reaction of α,α-dihalogenated aldimines with lithium aluminium hydride provided a facile synthesis of 1,1-disubstituted aziridines (a three step synthesis starting from ordinary aliphatic aldehydes).