Preparation Of Noble Metal Nanoparticles Supported On Mg-Al Mixed Metal Oxide Catalyst For Alcohol Selective Oxidation Esterification&Dehydrogenation Reaction

Firstly, a series of Au, Pd nanopaticles supported on Mg-Al mixed metal oxidecatalysts were prepared by co-precipitation. Then the catalysts were characterized bytransmission electron microscopy (TEM), powder X-ray diffraction (XRD), N2physical adsorption (BET) ect.method. Finally, catalytic activities of these catalystswere evaluated. The specific research contents and conclusions were as follows:1. Preparation and characterization of the Pd nanopaticles supported on Mg-Almixed metal oxide catalystThe Pd nanopaticles supported on Mg-Al mixed oxide catalyst were prepared byco-precipitation. XRD, XPS and TEM etc. were used to characterize the materials,and the results indicated that the Pd nanopaticles were homogeneous dispersed on thesurface of the supports.2. Catalytic activity of the Pd nanopaticles supported on Mg-Al mixed metaloxide catalyst in synthesis of N-benzylideneanilineFirstly, different catalysts were studied in the synthesis of N-benzylideneanilineby benzyl alcohol and aniline, and R-Pd-LDO catalyst showed the best catalyticperformance. Using R-Pd-LDO as catalyst, studied the effects of different reactionconditions (including different kinds of solvents, reaction temperature and reactiontime). The optimum reaction conditions was: methanol as the solvent,120℃, N2protection,6h, the yield of N-benzylideneaniline was>99%. And the result ofreusing experiment revealed that the obvious losses of conversion and selectivity werenot observed, the supported Pd nanopaticles catalyst shows high stability.3. Preparation and characterization of a series AuPd nanopaticles supported onMg-Al mixed metal oxide catalystsFirstly, AuPd-LDOx(x=1,2,3,4,5,6) catalysts were prepared by co-precipitation, and supported single Au or Pd catalyst were prepared by the samemethods. Then prepared AuPd nanopaticles supported on Mg-Al mixed metal oxidecatalyst by using wet-impregnation method. The structure and composition of thosecatalysts were characterized by XRD, BET and TEM etc. The results indicated thatboth co-precitation and wet-impregnation methods can prepare AuPd alloy catalysts.And the mean AuPd nanopaticles size, the basicity and the surface area of AuPd- LDOx(x=1,2,3,4,5,6) catalysts were influenced by the texture and nature ofdifferent ratio of Mg and Al supports.4. Catalytic performance of the AuPd nanopaticles supported on Mg-Al mixedoxide catalyst in the oxidative esterification of alcohol to form ester.Firstly, the catalytic activity of those catalysts in the oxidative esterification ofbenzyl alcohol and methanol were studied. The results indicated that: the differentratio of Mg and Al catalyst shows different catalytic activity, AuPd-LDO2shows thegreat activity. Using AuPd-LDO2as catalyst, studied the effects of different reactionconditions (including the different reaction temperature, reaction times, O2pressure)of synthesis of methyl benzoate. The optimum reaction conditions was: methanol assolvent,0.5MPaO2,100℃,2h, the yield of methyl benzoate reached>99%. Therecycle experiment revealed that AuPd-LDO2catalyst shows highly stability. Finally,AuPd-LDO2catalyst is very efficient for oxidative esterification of various primaryalcohols (including benzylic, allylic and heterocyclic alcohols) under similar mildconditions. Besides, AuPd-LDO2was not only showed highly catalytic activity insynthesis of methyl esters, but also showed great catalytic performance in synthesis ofaliphatic benzoate.