| Guathol and guaiacol are important synthetic intermediate in fine chemical production. They are widely used in the production of flavouring agents, fragrances, agricultural chemicals and pharmaceuticals. Traditionally, guathol and guaiacol were synthesized by homogeneous phase and batch processes, which had complicated technological process and were corrosive, toxic and environmental hazardous. Recently, vapour-phase alkylation of catechol with methanol and ethanol for the synthesis of guaiacol and guathol has received more attention, since this route is more economical and more environmentally friendly for industrial applications. This process will be the main direction of scientific research and industrial production in future.Some heterogeneous catalysts have been tested in the vapour-phase alkylation of catechol with ethanol (methanol) early. However, a common problem is that most of the tested catalysts exhibited unsatisfactory activity and/or unfavourable rapid deactivation. These drawbacks restrict the application of this route to produce guathol(guaiacol). Recently, our research team found that Al-P-Ti and Al-P-Ti-Si showed high catalytic activity and stability in the vapour-phase of catechol and ethanol (methanol), which indicates a good prospect. However, from the perspective of industrial applications, the preparation process of the catalysts is relative complexity and the shaping technics need to study systemically. Otherwise, the relationship between the acid-base properties of the catalysts and their catalytic performance for the reaction needs to study further.Base on preliminary work, we focus on preparing the Al-P-O catalysts with different texture and acid-base properties by improving and optimizing the preparation method. The vapour-phase O-methylation of catechol with ethanol (methanol) has been investigated over these catalysts. Magnifying and shaping of the catalysts which showed better catalytic performance are also studied. The relationship between the texture, acid-base properties and the catalytic performance of catalysts were studied by different characterization means of XRD, BET, TPD, SEM and FTIR of pyridine and ammonia adsorption etc. Meanwhile, the nature of active center and the reaction mechanism were also discussed.TFirstly, Al-P-O catalysts were prepared with a simple precipitation method. The catalytic properties of Al-P-O samples synthesized with different P sources, pH and P/Al ratio in the vapour-phase O-ethylation of catechol with ethanol were investigated. Al1P1.1 prepared with NH4H2PO4 and shows higher activity. With the incresacing of pH, the activity of the reaction increase and the catalyst prepared with 7 showed the highest activity. Magnifying, repeatability and shaping of the catalysts were also studied. Samples prepared with different batchs give higer activity and yield of guathol (above 80%), so this preparation method shows good repeatability. Silica gel, nitric acid and sesbania gum powder as shaping additives were attempted to shape the catalyst. With the increasing amount of silica gel and nitric acid, the mechanical strength of shaped catalysts increase and the conversion of catechol decrease gradually. When the amount of silica gel were 0-10% and nitric acid were 8.7-17.4%, the mechanical strength of shaped catalysts and the conversion of catechol were comparatively higher. The shaped catalysts were satisfied with amplificatory reaction.The catalyst shows the excellent durability. The stability of the catalysts is investigated for the vapour-phase alkylation of catechol with methanol and the vapour-phase alkylation of catechol with ethanol. The catalyst can keep high stability for more than 450h and 2000h respectively. Mesoporous aluminophosphate materials have been synthesized in the presence of citric acid. The results of characterization showed that P/Al molar ratio could adjust the acidic-basic property. The vapour-phase selective O-methylation of catechol with methanol reaction and catechol with ethanol reaction are carried out separately to investigate the catalytic performances of AlPO materials with different P/Al ratios. The conversion of catechol and the production distribution were compared in these two reactions systemically. Among AlPO materials with different P/Al ratios, AlP1.1O shows the highest activity and the highest yield of the main product in the two reactions. The conversion of catechol and the production distribution on AlP0.9O,AlP1.0O and AlP1.05O samples have distinct difference bewteen the two reactions. When catechol reacted with methanol, the conversion of catechol increased with the increasing P/Al ratios and the selectivity of guaiacol are all above 60%. When catechol reacted with ethanol, catechol is nearly reacted to produce C-alkylation productions. It supposes that ethanol produce carbenium ions easily on these catalysts, so the carbenium ions are probability to attack the atom of the catechol and produce C-alkylation productions. Meanwile, the conversion of catechol is very high. On AlP1.1O and AlP1.15O samples,there have no difference of catechol conversion and the production distribution. The conversion of catechol are both above 85% of the two reactions, and the yield of guaiacol and guathol are 73.8% and 64.1% respectively. According to the characterization results, weak acid-base sites are the active centers of O-methylation of catechol with methanol and ethanol. The weaker acid-base centers are required of the latter reaction than that of the former reaction.AlPO-5 molecular sieve prepared by solvothermal method was investigated on the vapour-phase O-methylation of catechol with methanol. AlPO-5 was highly selectivity of the main product guaiacol (96%), but the conversion of catechol was lowly (38%). Different hydroxy-carboxylic compounds (citric acid, glucose and polyethylene glycol) were attempted to modify AlPO-5. The samples synthesized with polyethylene glycol was the highest conversion of catechol(68%) and the selectivity of guaiacol was highly (94%).Other weak acid-base catalysts were investigated in the vapour-phase O-methylation of catechol and methanol. AMT impregnated C, TiO2 and SiO2 catalysts were highly active and selective for the vapour-phase O-methylation of catechol with methanol. The activity of AMT impregnated C and TiO2 decreased obviously in 24h, no obviously activity loss occurs with the running term of 47h on AMT/ SiO2 sample. With further increasing reaction time, the activity of the catalyst decreased gradually, which may be mainly caused by the coke formation on the surface of the catalysts. In order to remove the carbon deposition, the used catalyst was calcined at higher temperature. The conversion of catechol increased slightly, but the stability decreaed. This result is consistent with the performance of catechol and methanol over the catalyst calcined at higer temperature. According to the result of CO2-TPD and NH3-TPD, the catalyst calcined at higer temperature present a certain amount of relatively stronger acid-base centers. These results further suggest that weak acid-base sites are acitive centers for the vapour-phase of catechol and methanol to produce guaiacol. Ti-Si samples possessed weak acid-base sites were also investigated in the vapour-phase O-methylation of catechol and methanol. Reaction activity decreased significantly within 6h, may be due to the sample surface on the Lewis acid sites caused by coke formation. Bronsted acid site of the materials with weak acid-base is active center in the O-methylation of catechol with methanol.
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