Preparation Of PANI-Co Catalyst And Catalysis Of α-oxime Epoxidation

Turpentine is not only the important renewable resource,but also precious industrial chemicals.α-Pinene and β-Pinene are the main components of turpentine,which special chemical structure makeits chemically active enough to take part in many reaction,such as isomerization,hydrogenation and oxidation reaction.Turpentine can be used in a variety of chemical synthesis industry,mainly for the synthesis of chemical intermediates,camphor,borneol,spices and rubber.Pine resources are abundant in our country,and turpentine oil has a high yield,but its utilization rate of the deep processing is low.Therefore,it is of broad prospect to the study on the catalyst for turpentine epoxidation to prepare 2,3-epoxypinane because of the high additional value of product,and it is bound to play an important role in accelerating the development of deep processing of oleoresin.Polyaniline（PANI）,as a new type of polymer material,has been widespread concernd in the catalytic system.Its unique physical and chemical properties are outstanding,and could allow the preparation of composite-materials with good catalytic performance.Structural formula of PANI in benzene type structure and quinoid structure,make the oxidation of PANI with adjustable reducibility,so metal ions can form of reversible cycle oxidation-reduction chain with PANI.can make the metal reciprocal transformation between different valence state.The molecular structure of PANI contains an imide group,which can form d.π-conjugated coordination polymer with the metal salt.The molar ratio of metal ion to PANI is different.and the coordination mode of metal salt and PANI is different.So PANI can form coordination with the metal,it can not only form between the metal PANI-metal nanoparticle complexes,but also can form a coordination polymer with the metal.Polyaniline nanofibers were synthesized through rapid mixing method,which was used in the preparation of PANI-Co catalystsand the catalysts were applied to turpentine epoxidation reaction.The morphology,structure and properties of the catalysts were characterized by different techniques,and comprehensive analysis catalxystic activity.The following several aspects were researched:（1）Polyaniline can be produced through rapid mixing method in different acid solutions.The effects of different factors on the preparation conditions of the PANI-Co catalysts were investigated,such as:doping of acid,pH value,redox properties of polyaniline,the ratio of polyaniline and Co,etc.At the flowing conditions:sulfuric acid as doping of acid,PANI:KMnO4=4:1,PANI:Co（OAc）2＝1:1 and pH=4,the best catalyst can be obtained with best catalytic performance.（2）The process condition of turpentine epoxidation catalyzed by supported PANI-Co catalysts were optimized by single factor experiment and orthogonal test,the optimum condition of reactions was obtained:reaction temperature 15 ℃,reaction time 1 h,the amount of catalyst3.7%,solvent dosage 15 mL,amount of cocatalyst 1.08g.Under the condition,PANI-Co catalyst exhibited the best activity that the conversion of a-pinene was up to 100%and the selectivity of epoxypinane was 84.95%.The catalyst was found to be reusable for five cycles,the conversion of a-pinene showed an inconspicuous fluctuation in the range of 97.4-100 mol%,while the selectivity of epoxypinane was kept a more or less constant around 80.1-85.0%.（3）The structure and properties of the PANI-Co catalyst were characterized by SEM、TEM、XRD、FT-IR、XPS、TG-DSC、H2-TPR and O₂-TPD techniques,and the relationship between the catalytic performance and the structure of PANI-Co catalyst was explored.