78480-27-0Relevant academic research and scientific papers
Green synthesis of bisphenol F over 12-phosphotungstic acid supported on acid-activated palygorskite
Liu, Ran,Niu, Xiaozhen,Xia, Xinnian,Zeng, Zebing,Zhang, Guozhong,Lu, Yanbing
, p. 62394 - 62401 (2015/08/06)
In this study, acid-activated palygorskite (Pa) with tunable surface acidity was obtained by simple acidic treatment of raw clay. The new catalysts with 5-30 wt% 12-phosphotungstic acid (H3O40PW12·xH2O, PTA) were then readily prepared by the wet impregnation method. Their characteristic features were systematically investigated by various means including energy-dispersive X-ray (EDX), X-ray diffraction (XRD), N2 adsorption/desorption isotherms, Fourier-transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), as well by comparison with Pa, PTA and H-Beta zeolite. The high activities of these catalysts promoted phenol to undergo hydroxyalkylation, resulting in an interesting bisphenol F (BPF) product. Among these solid acid catalysts, 10% PTA/Pa was chosen as the most suitable catalyst giving an 87% yield and 96% selectivity under mild conditions (phenol/formaldehyde mole ratio of 15: 1; T = 343 K; catalyst concentration of 0.006 g g-1; 40 min). The surface acid strength and acidic type were characterized by ammonia temperature programmed desorption of NH3 (NH3-TPD), and FT-IR of pyridine adsorption (Py-IR). It was found that the catalytic activity could be further enhanced by impregnating PTA onto Pa due to the enhanced acid strength and the redistribution of Br?nsted and Lewis acid sites. Besides, a more appropriate combination of Br?nsted and Lewis acid sites was essential to achieve the highest BPF yield. Recycle experiments were conducted and a plausible mechanistic pathway was proposed according to our observations and findings.
Metal Arene Complexes in Organic Synthesis. Hydroxylation, Trimethylsilylation, and Carbethoxylation of Some Polycyclic Aromatic Hydrocarbons Utilizing η6-Arene-Chromium Tricarbonyl Complexes
Morley, James A.,Woolsey, Neil F.
, p. 6487 - 6495 (2007/10/02)
The deprotonation of polycyclic aromatic hydrocarbon (PAH) chromium tricarbonyl complexes (PAH = naphthalene, anthracene, phenanthrene, pyrene, fluoranthene) using an in situ technique where the PAH complex, the base (LiTMP or LDA), and the electrophile (trialkyl borate, trimethylsilyl chloride, or ethyl chloroformate) were placed in solution simultaneously resulted in hydroxylation, trimethylsilylation, or carbethoxylation of the PAH after oxidative workup where the regiochemistry was controlled by steric factors.As a result, substitution at positions of the PAHs not readily available by electrophilic substitution were obtained in some cases.Conditions minimizing isomer mixtures and factors affecting the regiochemistry and the scope of the reaction sequence were examined.
