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Study On Co-production Of Nitrocyclohexane And Adipic Acid From The Nitration Oxidation Reaction Of Cyclohexane With NO2

Posted on:2013-10-06Degree:MasterType:Thesis
Country:ChinaCandidate:H J XiaoFull Text:PDF
GTID:2321330518988651Subject:Chemical Engineering and Technology
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Nitro-alkanes and dicarboxylic acids are used widely to manufacture material,medicine,dye,pesticide,surfactant and lubricant.Nitrocyclohexane is used as high performance organic solvent or dye,also can be synthetized to caprolactam by partial hydrogenation reaction,which is a new green process of higher utilization and less environment pollution;adipic acid is a dicarboxylic acid with the widest application prospect,which is manufactured to nylon66 as main raw material.The traditional production processes of nitrocyclohexane and adipic acid have many defects of low selectivity,severe equipment corrosion and serious environment pollution,especially the production process of adipic acid exhibited low conversion rate and high acid consumption,producing waste acid and strong greenhouse effcet of gas N2O,so itís very urgent to develop a new nitration oxidation process.Co-production of nitrocyclohexane and adipic acid from the nitration oxidation reaction of cyclohexane with NO2 would avoid such defects with advantages of high conversion rate and simple separation of products,generally the selectivity of nitrocyclohexane and adipic acid was high up to 95%.In this paper,the continuous non-catalytic reaction of cyclohexane and NO2 in gas phase was studied,the better reaction conditions by the single factor optimization were as follow:molar ratio is 1:1,reaction temperature is 250?,residence time is 68 s,cyclohexane conversion is 10.2%,nitrocyclohexane selectivity is 70.3%,adipic acid selectivity is 28.6%and total selectivity is high up to 98.9%.In this conditions,the continuous catalytic reaction in gas phase was studied,the results indicates that the VPO composite catalysts exhibited the best catalytic properties;and then modified to M-VPO composites by introducing the transition metals M?M=Cr,Mn,Co,Ni,Cu?or ?-Al2O3 exhibited higher adipic acid selectivity,especially Ni-AlVPO,gives the excellent results with 11.6%of cyclohexane conversion,44.9%of nitrocyclohexane selectivity and 52.4%of adipic acid selectivity under the conditions that the molar ratio is 1:1,reaction temperature is 250? and residence time is 68 s,the 97.3%of total selectivity for nitrocyclohexane and adipic acid were obtained.The characterization of XRD,UV-vis absorption spectra and BET on catalysts showed that:the transition metals and ?-Al2O3 introduced to VPO and AlVPO precursor resulted in changes of the catalytic active component in different extent and the catalytic properties were improved.Some preliminary exploration on batch non-catalytic reaction of cyclohexane with NO2 at atmospheric pressure in solvent phase was carried out.The best reaction conditions with the ratio of NO2 with cyclohexane 2:3,reaction temperature 87 ?,reaction time 18 h,the best results with 3.1%of cyclohexane conversion,38.9%of nitrocyclohexane selectivity,59.5%of adipic acid selectivity and total selectivity 98.4%were obtained by the single factor optiminzation.The radical reaction mechanism on the nitration oxidation reaction of cyclohexane with NO2 was proposed according to expenriment and charaterization results.
Keywords/Search Tags:cyclohexane, NO2, nitrationoxidation, nitrocyclohexane, adipic acid
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