The Preparation Of Ru-Ni Based Catalysts For ?-pinene Hydrogenation And Sulfur Resistance Evaluation

Turpentine is the most common spices synthetic raw material,and its important products chain and extension is a serious of products via turpentine oil hydrogenation.Pinene is the main element of the turpentine oil,its catalytic hydrogenation product is pinnae,an important intermediates for terpenoids spices industry.As high as possible for cis-pinena content is the requirement for commercial.Therefore,reasonable design and accordingly development of highly active and selective hydrogenation catalyst is extremely important for this process.Except for the study of the hydrogenation catalyst itself,some common problems of hydrogenation catalystis can also be obtained in such an investigation thus with considerable academic research and industrial application values.The first part of this work is the selection of the active component for the catalystused for this reaction.Choosing nickel chloride hexahydrate as the source of nickel,hexahydrate ruthenium chloride as source of ruthenium,H? zeolite as support,a series of oxidation state Ru-(X)Ni/H? catalysts were prepared by altering nickel load,and using hydrazine hydrate as reduction agent.The characterization results for these catalysts shows that:The change of Ni content will change catalyst acidic species and the intensity of acid,the activity sites for the activation of ?-pinene,as well as the interactions between the support and Ru species.When the content of Ni is low,Bronsted acid is the main active sites for a-pinene activation.As Bronsted acid on pinene has a higher activation capacity,the heat generated by the reaction will be released instantaneously,which leads to theresult of trans-pinena in dominated in products.When the Ni content is high,the activation of a-pinene is achieved through the Lewis acid center,part of which is achieved by the NiO existence.The ?-pinene activation ability of Lewis acid is weaker than Bronsted acid,thus reducing the reaction rate when Lewis acid appears.NiO is more conducive to play its steric hindrance to adsorb and activate a-pinene.Therefore,mainly cis-based products can be obtained when existing NiO for the activation of a-pinene.The second part of this work is the catalyst molding process.3%Ru-4%Ni bimetallic catalyst,which had the highest activity and selectivity,was selectecd as the active component of the molding catalyst,where H? zeolite was used as the support.A large particle catalyst with uniform mechanical strength,shape and particle size was prepared by extrusion molding.To evaluate the durability performance,the catalyst catalyst was continuously in used of reaction for 1000 h.The results showed that the conversion of ?-pinene remained above 99%and the selectivity of cis-pinana kept about 96%-96%,for the molding catalyst,which meant fairly good acyivity and stability.The third part of this work is the evaluation of the catalyst for sulfur resistance.Sulfur-containing pinene prefers hydrogenation isomerization reaction and easy to reach a large number of by-products.Results shows that,the stronger the support acidity and the higher the reaction temperature and pressure,lead to the lower selectivity of cis-pinana,and the more prone to the isomerization reaction.Based on these,the selectivity of cis-pinana can be controlled by selecting the appropriate acid support,retaining the reaction temperature and pressure to effectively control the occurrence of isomerization of sulfur-containing pinene.