Alkenylation Of Aromatics With Phenylacetylene Over Novel Solid Acid Catalysts

Alkenylaromatics, are a kind of important fine chemical intermediates for synthesizing agrochemicals, pharmaceuticals, flavors, and dyes. The direct alkenylation of arenes with alkynes is a simple and green pathway to synthesize desired products with the high atom economy. Precious metals or organic metal complexes catalysts have many shortcomings such as the high cost of ligand and precious metals, the reaction efficiency greatly influenced by the substrates, therefor it is difficult to be used in actual production. The liquid acids have been exploited in the alkenylation, many problems still exist, such as the corrosion of equipments, pollution of the environment, complexity in the isolation of products and cyclic utilization of catalyst, zeolite solid acid catalysts have low catalytic efficiency, H3PW12O40/MCM-41 catalyst has low catalytic stability and complexed in cyclic utilization..The alkenylation of aromatics with phenylacetylene over La-modified SO42-/ZrO2 and natural clay (H-Clay) was investigated. Various characterization techniques such as N2 adsorption-desorption, X-ray diffraction (XRD), FT-IR, NH3 temperature-programmed desorption (NH3-TPD) were employed to reveal the relationship between catalyst nature and catalytic performance. The main conclusions are summaried as follows:1. La-modified SO42-/meso-ZrO2 solid acid catalyst possesses an ordered mesoporous architecture and exhibits much better catalytic activity compared with unmodified SO42-/meso-ZrO2. we investigated the effect of nLa/(La+zr) in the process of catalyst preparation and reaction parameters on the alkenylation. When the nLa/(La+zr) is 0.10, La-modified SO42-/meso-La2O2-ZrO2 solid acid catalyst exhibits the best catalytic activity.98.4% conversion of phenylacetylene with 92.5% selectivity of main product a-arylstyrene(I) can be obtained under optimized reaction conditions, i.e. reaction temperature (Tr) 170 ℃, system pressure 1.0 MPa, volume hourly space velocity (VHSV) 6 ml·h-1·g-1 cat.. Especially the used catalyst can be easily but complete recovered by a facile and low-cost calcination process.2. we investigated the effect of the preparation conditions of mesoporous metal oxide meso-La0.1Zr0.9O2 for alkenylation of p-xylene with phenylacetylene over the developed SO42-/meso-La0.1Zr0.9O2 solid acid catalyst. The SO42-/meso-La0.1Zr0.9O2 solid acid catalyst exhibits the best catalytic activity When the mole ratio of surfactan/metal ions is 0.175, hydrothennal temperature is 90℃, hydrothermal time is 60 h, calcination temperature is 550 ℃.3. we investigated the effect of the exchanging number (Nc) of ammonium nitrate and calcination temperature (Tc) on the catalytic performance of H-clay solid acid catalysts for the alkenylation. The H-Clay solid acid catalyst exhibits the best catalytic activity When Nc is 2 and Tc is 550 ℃, under this conditions,95.6% conversion of phenylacetylene with 95.9% selectivity of main product α-arylstyrene (I) can be obtained. The used H-Clay catalyst can be recovered by calcination process.