水煤浆添加剂萘磺酸甲醛缩合物合成条件的优化

以精萘、浓硫酸和甲醛为原料,依次经过磺化、水解、缩合三个反应合成了萘磺酸甲醛缩合物(NSF),并获得了各反应的优化条件。结果表明:当2-萘磺酸(2-NSA)产率最大时,磺化反应的优化条件为n(萘)∶n(浓硫酸)=1∶1.15、反应温度160℃、反应时间3 h;水解反应要使1-萘磺酸(1-NSA)的残留量最低优化条件为反应温度115℃、反应时间60 min、n(萘)∶n(水)=1∶2.3,此时1-NSA水解的转化率最高;缩合反应的优化条件为n(萘)∶n(甲醛)=1∶1、酸度30%,反应温度105℃,反应时间2 h,在此条件下2-NSA全部聚合生成NSF。产物NSF的红外光谱(FTIR)和高效液相色谱(HPLC)分析表明,不同条件下获得的NSF都含有丰富的芳环、亚甲基和磺酸基结构;HPLC分析表明,NSF在磺化度、分子量大小和分子的主体结构(线性结构/枝状结构)方面存在差异,这种差异导致NSF在作为水煤浆分散剂时,对降低浆体黏度和提高浆体稳定性方面具有不同的性能;优化条件下得到的NSF在降低浆体黏度方面性能优于市售的萘磺酸甲醛缩合物系分散剂(NX-1),但二者对保持浆体稳定性的能力相当。

Synthesis Optimization of Naphthalenesulfonic Acid Formaldehyde Condensate as Coal Water Slurry Dispersant

Naphthalenesulfonic acid formaldehyde condensates(NSFs)was synthesized from refined naphthalene,concentrated sulfuric acid and formaldehyde by 3 step sequential reactions of sulfonation,hydrolysis and condensation,and the optimum reaction conditions were obtained.Experimental analysis show that when the yield of 2-NSA is maximized,the optimal conditions for the naphthalene sulfonation reaction are n(naphthalene)∶n(concentrated sulfuric acid)=1∶1.15,reaction temperature is 160℃,reaction time is 3 h;the hydrolysis reaction should minimize the residual amount of 1-NSA.Temperature is 115℃,reaction time is 60 min,n(naphthalene)∶n(water)=1∶2.3,the conversion rate of 1-NSA hydrolysis is the highest;the optimal conditions for the condensation reaction are n(naphthalene)∶n(formaldehyde)=1∶1,the acidity is 30%,the reaction temperature is 105℃,and the reaction time is 2 h.In these conditions,all 2-NSA polymerizes to form NSF.The products NSFs were analyzed by infrared spectroscopy(FTIR)and high performance liquid chromatography(HPLC).The results show that NSFs are abundant in aromatic rings,methylene and sulfonic group structures in different conditions.However,the results of HPLC showe that there are significant differences in the degree of sulfonation,molecular weight and main structure(linear structure/dendritic structure),which affects the properties of NSF in reducing the viscosity and improving the stability of slurry when NSF is used as dispersion agent of coal water slurry.Compared to the commercial dispersant NX-1,the NSF is superior in viscosity reduction,whereas,exhibites a comparable performance in maintaining the stability of CWS.