丁二烯法是先使丁二烯氯化生成二氯丁烯异构体混合物,再与氢氰酸或氰化钠在酸性水溶液中氰化成丁烯二氰异构体,用氢氧化钠处理,使异构体全部转化成1,4-二氰基丁烯-2,精制后用钯炭作催化剂,在300℃下氢化成己二胺。
由二元酸和二元胺制取尼龙时,需要严格控制原料配比为等摩尔比,才能得到分子量较高的聚合物,在生产中必须先把己二酸和己二胺混合制成尼龙66盐。尼龙66盐的制备是分别把己二胺的乙醇溶液与己二酸的乙醇溶液在60℃以上的温度下搅拌混合,中和成盐后析出,经过滤、醇洗、干燥,Zui后配制成63%左右的水溶液,供缩聚使用。
尼龙66盐的缩聚需在高温下进行,伴随着水的脱除,生成线型高分子量尼龙66。
The butadiene method involvesfirst chlorinating butadiene to form a mixture of dichlorobuteneisomers, then cyaniding it with hydrocyanic acid or sodium cyanidein an acidic aqueous solution to form butene dicyanide isomers.Then, it is treated with sodium hydroxide to convert all isomersinto 1,4-dicyanobutene-2. After refining, palladium carbon is usedas a catalyst to hydrogenate at 300 ° C to hexamethylenediamine.
When producing nylon frombinary acids and diamines, it is necessary to strictly control themolar ratio of raw materials to obtain polymers with highermolecular weight. Therefore, in production, it is necessary tofirst mix adipic acid and diamine to produce nylon 66 salt. Thepreparation of nylon 66 salt involves stirring and mixing anethanol solution of hexanediamine and an ethanol solution of adipicacid at a temperature above 60 °C, neutralizing to form a salt,precipitating, filtering, alcohol washing, drying, and finallypreparing an aqueous solution of about 63% forpolycondensation.
The condensation of nylon 66salt needs to be carried out at high temperatures, accompanied bythe removal of water, to generate linear high molecular weightnylon 66.
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