Preparation Of Ni-based Catalysts By Electroless Plating And Research On Rosin Hydrogenation

Rosin is transparent,brittle solid natural resin composed of a resin acid,a small amount of fatty acid,rosin anhydride,and a neutral substance.Its main component is resin acid,accounting for about 90%,the molecular formula is C ₁₉H₂₉COOH.It is an unsaturated acid,contains a conjugated double bond,has high reactivity,and is prone to hydrogenation,esterification,polymerization,disproportionation,etc.,and its hydrogenation product is important.The rosin modified product is an important fine chemical intermediate widely used in adhesives,synthetic rubber,paints,inks,paper,electronics,food and other fields.Research and preparation of high performance catalysts for the rosin hydrogenation reaction plays an important role in the deep processing and utilization of rosin.At present,rosin hydrogenation catalysts can be divided into noble metal catalysts and non-precious metal catalysts.Non-precious metal nickel-based catalysts are inexpensive and have a wide range of sources,and have been favored by people.In this paper,the composite carrier TiO₂-ZrO₂ with unique structure and unique optical properties was prepared by sol-gel method.Since TiO₂-ZrO₂ has a mesoporous structure and a large number of hydroxyl groups on the surface,it can provide more active sites for the load,thus making inorganic Metal ions and carriers can be better combined.In this paper,non-precious metal Ni-B/TiO₂-ZrO₂ and Ni-Mo-B/TiO₂-ZrO₂amorphous alloy catalysts were prepared by metal-induced electroless plating,and the catalysts were applied to the rosin hydrogenation reaction.The catalyst was characterized by different means,and the morphology,structure and properties of the catalyst were characterized by different techniques,and comprehensive analysis catalystic activity.The following aspects have been studied:?1?The composite carrier TiO₂-ZrO₂ was prepared by sol-gel method using butyl titanate as the titanium source and the inorganic salt zirconium oxychloride as the zirconium source.The suitable preparation conditions were investigated by single factor experiment at Zr/Ti molar ratio of 0.6,water bath temperature 60?,pH=3.5,aging time 24 h,calcination temperature 550?,calcination time 4 h.The rosin hydrogenation products were analyzed by GC and GC-MS,and the carried were charaterized by XRD,BET and TEM.The results show ed that the composite were amorphous and mesoporous structure with the specific surface area of 158.22 m²/g and average pore diameter of 6.95 nm,po re volume of 0.24 cm³/g.?2?The catalyst Ni-B/TiO₂-ZrO₂ was prepared by metal induced electroless plating with TiO₂-ZrO₂ as carrier and investigated suitable preparation conditions by single factor experiment and orthogonal experiment at NiSO₄/carrier mass ratio of 1:1,Ni/B molar ratio of 1:2,the microwave intervention temperature of 45?,and the concentration of NaOH of 0.5 mol/L.The optimization of the rosin hydrogenation process conditions was also carried out by single factor and orthogonal experiments.The suitable process conditions were as follows:reaction temperature was 200?,reaction time was 4 h,reaction pressure was 5 MPa,and catalyst dosage was 5%wt.The results showed that the average conversion rate of rosin was 99.60%,which also showed good reproducibility.The reusable 7 times of catalyst could maintain high catalytic activity and the hydrogenated rosin also could still maintain special grade.?3?The catalyst Ni-Mo-B/TiO₂-ZrO₂ was prepared by metal induced electroless plating with TiO₂-ZrO₂ as carrier and investigated suitable preparation conditions by single factor experiment and orthogonal experiment at Ni+Mo/carrier mass ratio of1:1.5,Ni+Mo/B mass ratio of 1:2,microwave intervention temperature is The concentration of 60?,the concentration of NaOH of 0.7 mol/L,and the mass percentage of Mo was 8%wt.The optimization of the rosin hydrogenation process conditions was also carried out by single factor experiment and BBD response surface methodology.The suitable process conditions were a s follows:reaction time was 3 h,reaction temperature was 197.93??take 198??.),reaction pressure 3.67MPa?take4 MPa?,catalyst dosage 4.56%?take 5%?,maximum response value,rosin hydrogenation reaction under this condition,conversion rate of 99.9 0%,which also showed good reproducibility.The reusable 8 times of catalyst could maintain high catalytic activity and the hydrogenated rosin also could still maintain special grade.?4?The rosin hydrogenation products were analyzed by GC and GC-MS,and the catalysts were characterized by BET,XRD,XPS,TEM,TG-DSC.The TEM showed that the carrier was honeycomb-shaped and the particle size was small with about 10nm.Combined with XRD,the active components Ni-B and Ni-Mo-B were successfully loaded onto the carrier TiO₂-ZrO₂ with amorphous form.On the one hand,the deactivated catalysts could due to agglomeration of the active component particles,the dispersibility is deteriorated,and the particle size became large.On the other hand,the valence states of Ni,Mo,and B were changed,and the contents of Ni⁰,Mo⁰,and B⁰ were significantly decreased and oxidized as Ni²⁺,Mo⁶⁺,and B²⁺.Therefore,the catalyst activity was lowered.It was known from XRD that after the deactivation,the catalyst exhibited a sharp peak of Ni at around 45°.