新型哌嗪衍生物的合成、表征及抗磨性的初步考察

 通过无水哌嗪与二硫化碳以及含不同酯基的氯乙酸酯反应，合成了6种新型无灰、无磷环境友好润滑油添加剂1,4-双(二硫代甲酸乙酸酯基)哌嗪衍生物2a,2b,2c,2d,2e,2f。采用1H NMR、13C NMR、IR、UV、MS和元素分析对它们进行表征，确证了其结构，并采用热重分析仪考察了其热稳定性能。利用四球摩擦磨损试验机考察了其在液体石蜡(LP)中的承载能力和添加剂浓度、摩擦时间及载荷对液体石蜡抗磨性能的影响。结果表明，它们的初始分解温度均高于300℃，第二分解温度最高达到370℃，说明它们的热稳定性能良好。此类添加剂具有很高的承载能力，当添加剂用量为1.0%（质量分数）时，样品2c+LP的PB值最大可达1100N，远比ZDDP+LP样品的PB值高；并且它们能够明显改善LP的抗磨性能，性能最好的是2f。1,4-双(二硫代甲酸乙酸酯基)哌嗪衍生物中烷基链的长短和形状(直链或支链)对其承载能力的影响不大，但对抗磨性能有很大的影响，含有长链烷基的哌嗪衍生物抗磨性能更好。

SYNTHESIS, CHARACTERIZATION OF NOVEL PIPERAZINE DERIVATIVES AND THEIR ANTI-WEAR BEIIAVIOR IN LIQUID PARAFFIN

Six piperazine derivatives, 1,4-di(dithiocarbamate acteate)piperazines, named 2a, 2b, 2c, 2d, 2e, 2f, were synthesized from the reaction of piperazine with carbon disulfide and chloroacetate, whose structures and thermal stability were determined by 1H NMR, 13C NMR, IR, UV, MS, elemental analysis and thermogravimetric apparatus, respectively. These piperazine derivatives were used as the novel, environmentally friendly and ash-less and non-phosphorus lubricating oil additives in liquid paraffin(LP). Their load-carrying capacity as lubricating oil additives and the effects of additive concentration, friction time and load on the anti-wear performance of LP were evaluated by using a four-ball tester. The results showed that the six derivatives all thermally decomposed at above 300℃, and the highest decomposition temperature was about 370℃, indicating the fair thermal stability. The six derivatives all possessed excellent load-carrying capacity, and the maximum PB value of the LP sample with 1.0% (mass fraction) 2c added, reached 1100N，much better than that of the LP sample with 1.0% ZDDP. They could improve the anti-wear performance of LP, among which 2f was the best one. The length and shape of alkyl in the molecule of 1,4-di(dithiocarbamate acteate)piperazine had less impact on PB value but length of alkyl was the main factor affecting the anti-wear performance of LP. With the longer length of the alkyl, the anti-wear ability of 1,4-di(dithiocarbamate acteate)piperazine for LP was better.