Mannich Reaction And Crosslinking Kineteics Of Its Products From Lingnin Model Compouns

In this paper, guaiacol and vanillin aminated polyols were prepared respectively from guaiacol or vanillin, diethanolamine and paraformaldehyde by the Mannich reaction. The chemical structures of the Mannich reaction products were characterized, and the crosslinking reaction kinetics of the aminated polyols reacted with MDI-50 were investigated by FT-IR method.The main contents and conclusions of this paper were listed as follows:1. Guaiacol aminated polyol(GAP) was prepared from guaiacol, diethanolamine and paraformaldehyde by the Mannich reaction, and its chemical structure was characterized. The effects of main reaction factors,i.e., dropping order, ratio of materials, reaction temperature and reaction time on the Mannich reaction were investigated. The results showed that the highest conversion rate of diethanolamine was up to 90.71 % by dropping 1,3-oxazolidine into guaiacol and reacting at 80～90 ?C for 3～4 hours in the molar ratio of n(guaiacol):n(formaldehyde):n(diethanolamine) as 1:1:1. The 1,3-oxazolidine was obtained from formaldehyde reacted with diethanolamine at 60 ?C for 2 hours.The chemical structure of guaiacol aminated polyol was characterized by HPLC, LC-MS, FT-IR and 1H NMR. The analysis results indicated that the aminomethyl group was introduced into ortho position of phenolic hydroxy group and the target product with molecular mass of 241 was synthesized successfully.2.Vanillin aminated polyol was prepared from vanillin, diethanolamine, and paraformaldehyde with 1,4-dioxane as solvent by the Mannich reaction, and its chemical structure was characterized. The effects of ratio of materials, reaction temperature,reaction time and solvent dosage on the Mannich reaction were investigated.It was shown from the results that the highest conversion rate of diethanolamine was up to 84.92 % by dropping 1,3-oxazolidine into vanillin and reacting at 80 ?C for 3 hours in the molar ratio of n(vanillin):n(formaldehyde):n(diethanolamine) as 1:1:1.The solvent dosage was 100 mL per mol vanillin and the 1,3-oxazolidine was obtained from formaldehyde reacted with diethanolamine at 60 ?C for 2 hours . The analysis of LC-MS, FT-IR and 1H NMR indicated that the aminomethyl group was introduced into ortho position of phenolic hydroxy group and the target product with molecular mass of 269 was synthesized successfully.3. The crosslinking reaction kinetics of guaiacol and vanillin aminated polyols reacted with MDI-50 were investigated respectively by FT-IR method. The kinetic equations of two crosslinking reaction systems were obtained. The kinetic equation of guaiacol aminated polyol(GAP)/MDI-50 system: d 95.53exp(?)The kinetic equation of vanillin aminated polyol(VAP)/MDI-50 system: (?)The innovations in this paper were summarized as follows:1. Two novel lignin model compounds aminated polyols were synthesized from lignin model compounds guaiacol and vanillin by the modification of Mannich reaction. The results indicated that Mannich reaction mainly occurred on the ortho position of phenolic hydroxy group and the aldehyde group could not participate in Mannich reaction.2. The crosslinking reaction kinetics of guaiacol and vanillin aminated polyols reacted with MDI-50 were investigated respectively by FT-IR spectrum method and the crosslinking reaction kinetic models were established. The result exhibited that the crosslinking reactions of guaiacol and vanillin aminated polyols reacted with MDI-50 were similar in reactivity and all in accordance with n-order reaction kinetic model.