| Due to the depletion of non-renewable resource and the increasing of environmental problems,replacing fossil raw materials with renewable resources has aroused a strong interest.Rosin is a natural renewable resource,but the low softening point and high acid value limit its wide application.By modifying rosin into polymerized rosin,its value can be improved.Currently,the acid catalysts used in the reaction of rosin polymerization are liquid inorganic acids,solid acids,and ionic liquids.However,these catalysts go against with the concept of green chemistry and have a series of problems such as high cost,high toxicity,environmental pollution,corrosion of equipment and complicated post-treatment.Therefore,it is significant to design and synthesize green,non-toxic,economical,environmental and friendly catalysts.Deep eutectic solvent is a new type of green solvent with the advantages of low raw material cost,simple preparation,100%atomic utilization,non-toxic,biodegradable,etc.It has been widely studied in the fields of catalysts,organic synthesis,electrochemistry,biomass treatment,etc.In this paper,three types of deep eutectic solvents(DES)with specific acid-functions were designed and synthesized to catalyze the reaction of rosin polymerization,and the structure and thermal stability of the preferred catalysts([Zn Cl2][CH3COOH]2,[Tf OH]2[OA]2[Bet],[DCA]2[Zn Cl2]2[PEG1000])were investigated by FT-IR,~1H NMR and thermogravimetric analysis,and the acid strength of the catalysts were measured by potentiometric titration or UV spectrophotometry(Hammett function).(1)A series of double B-L acidic deep eutectic solvents were synthesized by selecting Br?nsted acids such as formic acid,acetic acid and propionic acid as hydrogen bond donors and Lewis acid(Zn Cl2)as hydrogen bond acceptors,to catalyze the reaction of rosin polymerization.[Zn Cl2][CH3COOH]2with the highest catalytic activity was selected,and then the effect of the different molar ratio of Br?nsted acid and Lewis acid of DES on the reaction of rosin polymerization was studied,and the optimal molar ratio of DES was 1:2.The reaction conditions of the rosin polymerization were optimized by controlling the variables uniquely.The results showed that the optimal reaction conditions were rosin 15 g,toluene 5.4 m L,n-octane 12.6 m L,catalyst 5 g,110 oC reaction temperature and 10 h reaction time,and the softening point of the polymerized rosin was 139.4 oC and the acid value was 129.9 mg KOH/g.Moreover,the catalyst[Zn Cl2][CH3COOH]2could be recycled five times under the optimal conditions and still had a good activity.(2)A series of ternary B-L acidic deep eutectic solvents were prepared by using the third component to link different Lewis acid and Br?nsted acid by hydrogen bonds,and the catalyst with the highest catalytic activity was[Cl2CHCOOH]2[Zn Cl2]2[PEG400].The effect of the different third component of DESs on the rosin polymerization reaction was investigated,and the best third component was PEG400 by examining both the recovery of the catalyst and the softening point of the polymerized rosin.Then the molar ratio of the third component in DES was kept constantly,and the effect of different molar ratio of Lewis acid,Br?nsted acid and the third component in the ternary B-L acid type deep eutectic solvents catalyzed rosin polymerization reaction system was investigated,and the determined optimal molar ratio was2:2:1.Then the effect of different molecular weights of PEG on the rosin polymerization reaction was investigated,and the optimal molecular weight was PEG1000.The reaction conditions of the rosin polymerization reaction were optimized by controlling the variables uniquely.The results showed that the optimum reaction conditions were rosin 15 g,toluene 5.4 m L,n-octane12.6 m L,catalyst 4.4 mmol,110 oC and 10 h.The softening point of the polymerized rosin was121.9 oC and the acid value was 136.4 mg KOH/g.The catalyst[Cl2CHCOOH]2[Zn Cl2]2[PEG1000]could be recycled ten times under the optimum conditions and still had a good activity.(3)A series of ternary B acidic deep eutectic solvents were prepared by self-assembly of a hydrogen bond acceptor with two hydrogen bond donors(two Br?nsted acids including organosulfonic and carboxylic acids with high acid strength),and the catalyst with the highest catalytic activity was[Tf OH]2[OA]2[Ch Cl]for rosin polymerization.The effects of different hydrogen bond acceptors on the rosin polymerization were investigated,and the best hydrogen bond acceptor was betaine(Bet)by examining both the recovery of the catalyst and the softening point of the polymerized rosin.Then the molar ratio of hydrogen bond acceptor in DES was kept constantly,and the effect of different molar ratio of two Br?nsted acids as hydrogen bond donors was investigated,and the determined optimal molar ratio of two hydrogen bond donors and one hydrogen bond acceptor was 2:2:1.The reaction conditions of the rosin polymerization reaction were optimized by controlling the variables uniquely.The results showed that the optimal reaction conditions were rosin 15 g,toluene 5.4 m L,n-octane 12.6 m L,catalyst 6 g,110 oC reaction temperature and 8 h reaction time,and the softening point of the polymerized rosin was167.5 oC and the acid value was 142.5 mg KOH/g.Moreover,the catalyst[Tf OH]2[OA]2[Bet]could be recycled seven times under the optimal conditions and still had a good activity.In this paper,DES with advantages of cheap raw materials,simple preparation,and environmentally friendly,has been used in the polymerization of rosin for the first time,and a good catalytic effect has been achieved.In ternary B acidic DES catalytic system,not only the polymerized rosin product with high softening point can be obtained,but also the catalyst has good recycling performance.This study provides a new way for the green production of polymerized rosin,and provides a theoretical basis for the practical application of acidic DES in rosin polymerization. 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