Process Improvement Of Accelerator DZ Preparation

Rubber vulcanization accelerator DZ was widely used in rubber products becauseof it’s excellent resistance to burning performance. But the drawbacks of low yield andthe by-products limitted it’s development. In order to solve these problems, this paperstudied the process of accelerator DZ preparation by one step method, improved thereaction conditions such as pH value and reaction temperature and obtained theoptimum reaction conditions about producing accelerator DZ with the highconcentration sodium hypochlorite. The yield of repeated experiments is87.1%, whichwas2%~5%higher than industrial yield. And the initial melting point of product isabove98°C, the content is98.1%via analysis of HPLC.According to analyze the mechanism, the increase of the pH value could increasethe concentration of reactant, and then improve the selective of accelerator M. Lowreaction temperature is beneficial for the product’s generation and reduce theconsumption of sodium hypochlorite, the increase of dicyclohexylamine could reducethe by-products in product. Via analyze the results of single factors experiments andorthogonal experiments, the optimum reaction conditions were obtained: the mole ratioof dicyclohexylamine and accelerator M is0.95:1, the mole ratio of availablechlorine and accelerator M is1.3:1, the pH value is10.4, the reaction temperature is37°C, the content of available chlorine in sodium hypochlorite is18%, theconcentration of the used dilute sulfuric acid is25%(mass fraction), the dose ofisopropyl alcohol is60ml, the drop time of sodium hypochlorite is1.5h.Compared with the two step method and oxygen oxidation method, it wasconcluded that one step method had the highest production and the lest raw materialsconsumption, which means the one step method are more fit for industrial production.The two step method has the best purity of the three methods, but the low production isthe main drawback. The better reaction conditions were obtained: the reactiontemperature is40°C, and the mole ratio of chlorinated dicyclohexylamine andM-sodium salt is1.2:1. The oxygen oxidation method has the lowest yield. And it needfurther study in the future because of it’s low pollution. The better reaction conditionswere obtained: the reaction temperature is40°C, the pressure is0.4Mpa, the moleratio of dicyclohexylamine and accelerator M is2.1:1, and the dose of catalyst is0.6mg. The waste water and residue which produced from one step method was handled.A few of toluene was used to dissolute the resin in the residue first, which containsaccelerator M, accelerator DM and dicyclohexylamine salts, then change the recycledisopropyl alcohol to dissolute it for one hour. And then the isopropyl alcohol was usedas solvent to prepare accelerator DZ. The experiments result indicates that this methodis beneficial to increase the yield, the yield of the experiments is87.9%, and there is nobad influence on the quality of the product.