Study On The Oxidation Of Alcohols To Aldehydes And Ketones By Green Chemistry Method

Oxidation of alcohols to aldehydes or ketones such as organic functional,grouptransformation experiments,have a negligible role in the fine chemicalindustry.Environmental issues have become important issues,people have to payattention to this.in recent years because environmental pollution has caused greatharm,some researchers begin to develop this topic. in the past,using transition metalcatalyst and2,2,6,6,-Tetramethylpiperidine nitroxide free radical catalyst areinevitably harmful to the environment.This paper designed a green route oxidizingalcohol to aldehyde and ketone compounds, can under mild reaction conditions,achieving high efficiency oxidation of alcohols, After reaction completing, thecatalyst easily separated from the product, and also can be used repeatedly,achieving the environmental protection,energy conservation.This paper was divided into two parts, using TiO2and TEMPO as alcoholoxidation catalysts respectively, discussing catalytic reaction system conditions withoptimization. The first part using TiO2/SiO2nanoparticles and FeCl3/HNO3ascatalyst, prepared TiO2/SiO2nanoparticles by precipitation method and using SEM,XRD observing characterization of morphology and crystalline, the SEM imagesshow that prepared TiO2/SiO2nanoparticles smooth and disperse well. in theoxidation of alcohols reaction, discuss the impact of the amount of catalyst on theyield of the reaction, when the same amount of substrate,0.2mmol alcohol,TiO2/SiO2nanoparticles0.05g, yield achieves the best. Because pH of the reactionsystem exist influence on reaction system, the experiment show that when smallamount of acid added into the reaction system, not only conversion rate significantincrease, but also the reaction rate significantly improved. So the acid has promotingeffect. In the oxidation of alcohols reaction, the alcohol substrate is0.2mmol, thereaction time is3h and the catalyst amount is0.05g,0.013g acid, the conversion rateis maximum of92.36%. Prepared TiO2-RGO nanoparticles, using XRD observing characterization of crystalline. Using TiO2-RGO catalyst in the oxidation of alcoholsreaction, the conversion rate of alcohols is94.07%. Using ultrasonic chemicalmethod, in the FeCl3/HNO3reaction system, the oxidation of alcohols to aldehydesand ketones in the reaction, the results show that when the ratio of FeCl3andHNO3is1:1, react15min, the conversion rate of alcohols reaches maximum.under thesame conditions, select the Lewis acid salts of CuCl2, ZnCl2, FeCl3, FeCl3/HNO3’syield is best. The yield of the alcohol to aldehyde/ketone is86%. FeCl3/HNO3system an excellent system for alcohol oxidation reaction,not only reaction time isshort time,but also reaction condition is mild.In the second part, SiO2@PAA/MAH-TEMPO和SiO2@PAA-TEMPOcore-shell nanoparticles were prepared, using FT-IR、SEM、EDX、TEM、 TGA、DSC analysis method to observe characterization of nanoparticles. Anelli oxidationof alcohol system applied in this unit. From SEM images can be seen that：thesynthesis of core-shell nanoparticles surface is smooth, spherical, and uniformdistribution without significant agglomeration. From the SEM images of SiO2@PAA/MAH and SiO2@PAA particles seen, there is a clear core-shell structure ofthe particles，that can explain PAA and PAA/MAH by copolymerization methodwas successfully bonded to KH570-SiO2nanoparticles. FT-IR spectrum ofnanoparticles indicated that OH-TEMPO successfully immobilized onto SiO2@PAA/MAH and SiO2@PAA particle surface because carbonyl peaks displacement.Comparing SiO2@PAA-TEMPO DSC curve with SiO2@PAA DSC curve, andComparing SiO2@PAA/MAH-TEMPO and SiO2@PAA/MAH nanoparticlesDSC curve, showed SiO2@PAA-TEMPO and SiO2@PAA/MAH-TEMPO noexothermic peak,while SiO2@PAA and SiO2@PAA/MAH exist exothermicpeak, which means OH-TEMPO successful immobilized onto SiO2@PAA/MAHand SiO2@PAA particle surface. By SiO2@PAA-TEMPO and SiO2@PAA/MAH-TEMPO TGA curves, different stages of weight loss SiO2particles withdifferent content of residual heat after weight loss, prove OH-TEMPO successfullyimmobilized in SiO2@PAA/MAH and SiO2@PAA particle surface. Finally, the oxidation of alcohols by Anlli reaction method showed that the conversion rate ofover90%in short time.