A facile and novel N-heteroarenium iodide-catalyzed hydroalkoxylation of enamides has been described. The protocol provides easy access to N,O-acetals, which proved to be a versatile synthetic synthon. The hydrosulfonylation, hydroamination, and hydrophosphorylation products of enamide could be indirectly provided from N,O-acetals. The reaction mechanism was further investigated, which indicated that the hydroalkoxylation of enamides was driven by weak coordination between enamide and the contact ion pair of N-heteroarenium iodide.
Wang Dai,Qiangqiang Liu,Xiaohui You,Zhongfei Zhou,Yanchun Guo,Yufen Zhao,Shuxia Cao
The Atherton–Todd-type reaction of hydrospirophosphoranes (HSPs) and sodium alcoholates was investigated. Direct alkoxylation of HSPs was accomplished with sodium alcoholates in acetonitrile under nitrogen atmosphere. The stereochemistry mechanism of the alkoxidation of HSPs was proposed by the 31 P NMR tracing experiment. The reaction proceeded via the chlorinated spirophosphorane intermediate with stereoretention of the configuration at phosphorus, followed by the rear and front attack of alkoxide anions to produce alkoxy spirophosphoranes. The reaction mechanism well explained the results of the reaction of HSPs with sodium alcoholates.
Yunfei Liao,Huiming Fan,Yongli Zhang,Hongyan Mou,Fengyu Li,Ziyin Zhou,Jianan Liu
PAAs can be further functionalized (hydroxylation and alkoxylation) by side chain substitution. In this study, we synthesized a SiPAAOH containing hydroxyl and siloxane groups based on the Aza-Michael addition reaction and applied it for reinforcement of aged paper. The results showed that the optimum conditions of SiPAAOH synthesis were as follows: the monomer molar ratio of APTES to EtA was 0.7:0.3, the solvent system for SiPAAOH reinforced aged paper was ethanol/water = 1:5 (v/v). The alkaline SiPAAOH could increase the pH of paper to 7.68, and to improve the amount of alkaline reserve to 200 mmol/kg. The whiteness and color difference of the treated paper were not significantly different from those of the untreated paper, and the mechanical properties of the paper were obviously improved. The results of contact angle and thermogravimetry showed that the SiPAAOH-treated paper was hydrophobicity and high temperature resistance.
Gong Yilu,Shao Tantan,Chen Xiaolong,Cao Shusen,Chen Lijun
The silicone modified acrylate dispersion was successfully prepared by semi-continuous seed emulsion polymerization, in which methyl methacrylate (MMA) was used as a hard monomer, butyl methacrylate (BA)was used as a soft monomer, and a double bond-containing polymerizable emulsifier ammonium allyloxtmethylate nonylphenol ethoxylates sulfate (DNS-86)and potassium persulfate (KPS)were utilized as emulsifiers and initiators, respectively. A functional monomer, benzyl methacrylate (BZMA), and a modified monomer, vinyltriethoxysilane (VTES), were introduced into the base dispersion. The factors, which have an influence on emulsion polymerization performance, were optimized. At the same time, the dispersions prepared with conventional emulsifiers and polymerizable emulsifiers were compared under the same conditions. The structure and properties of the synthetic dispersion were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and contact angle (CA). The results showed that the optimum preparation conditions of the dispersion are as follows: The amount of emulsifier was 3%, the amount of initiator was 0.5%, main monomer ratio was 1:1, the amount of functional monomer BZMA and VTES was 3%, respectively. The dispersion obtained by using DNS-86 had better thermal stability, chemical stability and the dispersion was uniformly blue, which represented small particle size. After modification, the film showed higher hydrophobicity.
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