Study On Cellulose Derivative Stabilized Metal Nanoparticles As A Catalyst For Hydrogenation Of ?-pinene

Turpentine is one of the most abundant biomass resources in China.Its main component is?-pinene.The cis-pinane produced by the hydrogenation of?-pinene has applications in the field of spices,medicine,pesticides and chemical industries,with a high economic value.This article explores"green",high-activity,high-selectivity,and high-stability catalysts.The micelle system formed by cellulose material obtained from renewable resources?renewable resources?was selected to prepare metal nanoparticles and catalyze the hydrogenation reaction of?-pinene to cis-pinane.Hydroxypropyl methylcellulose?HPMC?was used as the stabilizer,H₂ was used as the reductant,and the HPMC-Ru catalyst was prepared in an aqueous solution(T=60 ^oC,P=1.0 MPa,t=0.5 h,V_water=2 mL,c=5.0 g/L)with an average particle diameter of about 5.2 nm.The catalyst was prepared for the hydrogenation of?-pinene.The optimum reaction conditions were 2 mg sodium carbonate,n_??-pinene?/n_?Ru?=500,T=75 ^oC,P=0.5 MPa and t=4 h.The conversion was 98.62%,the selectivity for cis-pinane was 98.30%,and the stability of the catalyst was good.After usage 9 times,the conversion was still above 80%.Further,A simple kinetics study was carried out and it showed that it was a first-order reaction.Hydroxyethyl cellulose?HEC?was used as the stabilizer,H₂ was used as the reductant,and the HWC-Ru nanoparticle catalyst was prepared in an aqueous solution(T=50 ^oC,P=2.5 MPa,400–600 r/min,t=0.5 h,V_water=2 mL,c=3.0 g/L)with an average diameter of about 4.8 nm.The catalyst was used in the hydrogenation of?-pinene.The optimum reaction conditions were 2 mg sodium carbonate,n_??-pinene?/n_?Ru?=625,T=60 ^oC,P=2.0 MPa,400–600 r/min and t=4 h.The conversion was 99.56%,the selectivity was 98.58%,and the isolated catalyst phase could be used 10 times without any treatment,the conversion was still above 80%.The CMC-Ru nanoparticles was stabilized using carboxymethyl cellulose?CMC?in an aqueous medium.The catalyst was used in the hydrogenation of?-pinene.The conversion was 92.03%,the selectivity was 98.27%,and the isolated catalyst phase could be reused 6 times.Then,the Ru catalyst with methyl laurate-modified carboxymethyl cellulose?HM-CMC?as the stabilizer to protect Ru nanoparticles in the aqueous medium(T=60 ^oC,P=2.0 MPa,t=90 min,V_water=2 mL,c=1.0 g/L)was analyzed.Ru nanoparticles?3.2 nm?showed good stability and uniform distribution.The?-pinene was hydrogenated using the Ru nanoparticles stabilized by HM-CMC in the aqueous medium.The optimum reaction conditions were 2 mg sodium carbonate,n(?_-pinene)/n_?Ru?=625,T=75 ^oC,P=1.5 MPa,200–400 r/min and t=5 h.The results showed that the conversion of?-pinene reached 96.63%,the selectivity for cis-pinane reached 98.35%,and the catalyst could be reused 18 times,the conversion was still above 80%.The HM-CMC-Ni nanoparticle catalyst?T=60 ^oC,t=40 min?was prepared with HM-CMC as the stabilizer and NaBH₄ as the reducing agent.The catalyst was used in the hydrogenation of?-pinene.The optimum reaction conditions were 2 mg NaOH,T=80 ^oC,P=4.0 MPa and t=2 h.The conversion of?-pinene reached 96.87%,the selectivity for cis-pinane reached 97.77%.The above four systems are micelle-stabilized metal nanoparticle catalysts that show a high activity,high selectivity,and high stability in the hydrogenation of?-pinene due to the formation of the micelle"microreactor".Thus,this is an environmentally friendly novel approach for the hydrogenation of?-pinene and acts as a reference for the utilization of other substances in hydrogenation reactions.