Study On Synthesis And UV Curing Reaction Of Nopadiene

Turpentine, as a kind of renewable resources, its deep process and ulitilation are paid more and more attention. Nopadiene is a kind of turpentine deratives, which is wildly used in perfume chemistry, chiral synthesis, and it is also an important effective ingredient in a number of formulas. In this paper, the direct dehydration of nopol was studied to prepare nopadiene with a process optimization, and the elimination of nopol tosylate was improved and optimized to prepare nopadiene as a traditional method. The UV curing reaction of nopadiene and the properties of the cured product were also studied. This work will provie a reference for the application of terpenoid and its analogus as UV curing materials.Sulfuric acid (10 %), p-toluenesulfonic acid, potassium hydrogen sulfate, copper sulfate, silica-gel,copper sulfate-silica gel composite as well as silica-gel supported copper sulfate were compared as catalysts or dehydrating agents for the dehydration to prepare nopadiene. The result showed that the silica-gel supported copper sulfate was the best dehydration agent, with easy after-treatment and recovery. When the silica-gel supported copper sulfate was used as a dehydration agent, toluene was the best carrying-water agent, although xylene or amyl acetate made faster dehydration with more isomerization.While silica-gel supported copper sulfate was used as dehydrating agent and toluene was used as water-carrying agent, the optimizing experiment showed that the mass ratio of silica- gel and copper sulfate was 4:1; the yield of nopadiene increased at first and then declined with the increase of dehydration agent and reaction time (range of 1.0 h～8.0 h, suitable time is 4 h). Nopadiene was prepared in yield of 83.0 % with purity of 91.0 %(GC) when 5.0 g nopol was dehydrate in 70 mL toluene under the optimized conditions. This method may be suitable for a larger-scale preparation of nopadiene with the prospect of industrial development and application.Nopyl tosylate was prepared in triethyl amine (TEA) as both catalyst and solvent in a yield of 96.7 % because of its easy after-treatment compared with other two methods. When elimination reaction of nopol tosylate occurred under the of, Hereafter, nopadiene was prepared with the elimination of nopol tosylate in a yield decreasing by a sequence of potassium hydroxide, sodium ethoxide, potassium acetate and potassium carbonate. And nopadiene yielded in a yield of 72.9 % with a purity of 95.2% by potassium hydroxide as alkaline reagent and the dipole solvent DMSO as a solvent. This method may be suitable for preparation of nopadiene with higher purity.The UV curing reactivity of nopadiene has been also investigated in this paper, and it was found that conversion rates of vinylic double bond were 91.5 % and 90.7 % by using photoinitiators in dosages of 8.0 % Irgacure 6512 and 7.0 % Darocure 1173 based to the mass of nopadiene, respectively. The cured product photoinitiated by Irgacure 6512 and Darocure 1173 gave number average molecular weights of 1 286 daltons and 941 daltons with polymerization degrees of 9 and 6, respectively, and the uniformity was good. The obtained coating represented superior properties such as hardness, flexibility, mechanical, impact and acid resistance, alkali resistance.