| Rubber antioxidant RD, Chemical name is polymerized 2,2,4-trimethyl-1,2-dihydroquinoline Resin(Low molecular weight). It is chiefly used for rubber commonly protective agent . RD has excellent protective property to rubber oxidation caused by heat and oxygen , and better inhibiting action to catalystic oxidation derived from metals. It possesses lower volatility when used in higher temperature. RD is proper to rubber items used for higher temperature devices and in tropical aeras . This product has lower pollution and has not affect on sulfurization . RD is used in rubber products such as nat-rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber , chloroprene rubber etc. . It is commonly used in various tires , rubber products of industry and cable and so on , and also used in medical rubber products because of slight yellow .At present, aniline and acetone are used as raw materials in the production of RD , condensed at 150-165℃ in the presence of sulfinic acids , polymerized in hydrochloric acid solutions . The reaction mixture is neutralized with sodium hydroxide solutions , and RD is obtained These processes have pollution and devices' corrosion caused by acids such as hydrochloric acid , sulfuric acid etc., which resulted in lower economic . Therefore , it is essential to improve the technological processes . The synthetic conditions of rubber antioxidant RD catalyzed by solid acid were studied . Using solid super acid catalysts is simple in operation , easy to work up , and has no waste acidic liquor to drain off during reactions . The catalyst can be reused and regenerated , So it is essential to put it to use in the production of RD as quickly as possiple.Solid acids are a series of catalysts that acidic groups were bonded or supported on unsolvable supporters.There are several types solid acids .Mainlyrnew type catalysts, heteropolyacid solid super acids , Strong acidic ion exchange resin. SO42-/MnOm solid super acids have average properties of other solid acid catalysts and their owncharacteristics, such as higher used temperature ,easier and cheaper to gain .Since 1979 frist obtained , they have been noticing and studying by people. This paper selected kinds of catalysts and used as catalysts for synthesizing rubber antioxidant RD,and studied their catalystic properties of synthesizing RD, respectively. Solid super acid catalysts SO42-/TiO2 , SO42-/Fe2O3, SO42-/ZrO2 , S2O82-/ZrO2, zirconium sulphophenylphosphenate and strong acidic ion exchange resin are prepared and used in synthesizing rubber antioxidant RD. In comparison with sulfonic acid , the solid super acid catalysts show many advantages : readiness in isolating the products from the catalysts , convenience in treating the products , decrease of waste water , reduction in power consumption , etc..So solid acids are superior to traditional benzenesulfonic acid catalyst. But it was found in the study that SO42-/Fe2O3 , SO42-/TiO2 , SO42-/ZrO2 , S2Og2-/ZrO2, zirconium sulphophenylphosphenate were used as catalysts for the preparation of RD. The production of RD monomer is too low . Strong acidic ion exchange resin was best.The yield was 80% .The results are written as follows:1 . Solid acid catalystic SO42-/Fe2O3 was prepared and obtained easily and has lower price but catalystic properly is not ideal. The maximum conversion was 30% .2 . Solid acid catalyst SO427TiO2 . TiO2 particles are too thin .Although the yieldof RD when use SO42-/TiO2 as catalyst are more than that of using SO42-/Fe2O3 as catalyst, there is little economic in industrial product.3 . In the synthsis of RD , we used SO42-/ZrO2 as catalyst, the catalystic property of SO42-/ZrO2 was better than that of SO42-/TiO2 , and reused property was better, but SO42-/ZrO2 had the same drawback as SO42-/TiO2 ' s.4 . In the synthsis of RD, S2O82-/ZrO2 had better catalystic property , the yield of RD was 45% .5. Zirconium sulphophenylphosphenate was also used as catalyst , but it's catalystic property is worse. So it can not b...
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