Study On The Preparation Of Octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl) Propionate

Product name of octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is Antioxidant1076．It is widely used as the antioxidant inpolymer materials， such as polyethylene, polypropylene, polyester,polyurethane, polystyrene, ABS resin, polyamide，fiber，rubber andgrease paint． Antioxidant1076can prevent the plastic discoloration,embrittlement, loss of elongation, lower strength and deflection, andprevent changes in molecular weight, melt index and surface crackingand so on，which caused by intermolecular cross-linking or molecularchains of the split. Antioxidant1076has the advantages of non-toxic，good compatibility, high-performance antioxidation, non-colored,non-pollution, low volatility，heat-resisting and anti-water extraction. It iscalled the basic or primary antioxidants and it is one of the mainantioxidant products in current market.The preparation of octadecylβ-(3,5-di-tert-butyl-4-hydroxypheny)is that，2,6-di-tert-butyl-phenol(short for2,6-phenol) and methacrylate asstarting material through addition reaction in the presence of alkalinecatalyst， can get middle product methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate(short for3,5-ester)；then add octadecanol，throughtransesterification reaction can get mix product octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate；after the purification，can get finalpure product octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate（antioxidant1076）. Whether middle product is pured or separated，candistinguish two preparation methods, called two-step preparation andone-step preparation. One-step preparation is at the research stage insteadof industrialization，while two-step preparation has been industrializedand more mature.So improving its process for preparation, lowerproduction costs, will be extremely meanful.This paper used both two preparation methods（two-step preparation and one-step preparation），and researched influence on the experimentresults，caused by various factors of preparation, including：(1) influenceon the experiment results，caused by catalyst and its amount in additionreactions;(2) influence on the experiment results，caused by ratio of rawmaterials in addition reactions;(3)influence on the experiment results，caused by dropping time in addition reactions;(4)influence on theexperiment results， caused by reaction temperature in additionreactions;(5)influence on the experiment results，caused by reaction timein addition reactions;(6)influence on the experiment results，caused bycatalyst and its amount in transesterification;(7)influence on theexperiment results，caused by ratio of raw materials in transesteri fication;(8)influence on the experiment results， caused by vacuum intransesterification;(9)influence on the experiment results，caused byreaction temperature in transesterification;(10)influence on the experiment results，caused by reaction time in transesterification. Results of thestudy are as follows：Two-step preparation Addition reaction： choose potassiumhydroxide as catalyst,and catalyst amount should be0.97%of2,6-phenolin quality; ratio of raw materials should be n(2,6-phenol)： n(methacrylate)=1：1.1; dropping methacrylate temperature is110℃, time is1.5h; thermal reaction temperature shoud be130℃, thermal reactiontime shoud be4h.Crystallization solvent is water methanol（w（H2O）=17%）and solvent amount should2times of substrate in quality. Theyield of3,5-ester(based on2,6-phenol) is about95.5%, which increasedabout4%compared with literature. Transesterification： choose zincacetate as catalyst,and catalyst amount should be0.97%of octadecanol inquality; ratio of raw materials should be n(octadecanol):n(2,6-phenol)=1：1.1; thermal reaction temperature shoud be190℃, thermal reaction timeshoud be6h; reaction pressure should be21.0kPa. Crystallization solventis water methanol（w（H2O）=5%）and solvent amount should2times ofsubstrate in quality. The yield (based on octadecanol) is about97.0%, which increased about2%compared with literature.Two-step totalyield(based on2,6-phenol) is about84.2%, which increased about5%compared with literature.One-step preparation Addition reaction: the same with thetwo-step preparation,but the middle product should directly join thetransesterification instead of separation and purification. Transesterification: choose zinc acetate as catalyst,and catalyst amount should be0.97%of octadecanol in quality; ratio of raw materials should ben(octadecanol):n(2,6-phenol)=1：1.1; thermal reaction temperature shoudbe175℃, thermal reaction time shoud be4.5h; reaction pressure shouldbe31.7kPa. Crystallization solvent is water methanol（w（H2O）=5%）and solvent amount should2times of substrate in quality. One-step totalyield(based on2,6-phenol) is about80%, which increased about4%compared with literature.This paper has done characterization and quality analysis onoctadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, such asinfrared spectroscopy, high-performance liquid chromatography, NMR,melting point, etc. The Antioxidant1076products met the chemicalindustry standards HGT3795-2005.Innovations of this paper：（1）transesterification of octadecylβ-(3,5-di-tert-butyl-4-hydroxyl phenyl) propionate of traditionalindustrial production chose dibutyltin oxide as catalyst，however thispaper innovatively chose zinc acetate as the catalyst，and on this basisimproved its process for preparation，and the yield of the product. Zincacetate is a good catalyst with high efficiency, good economic returns,environmental protection and energy saving；（2） manufacturerscommonly used two-step preparation for industrial production, howeverbased on conditions on the tow-step preparation, this paper did moredetailed research on one-step preparation；（3）optimized the process conditions, and increased product yield.