高纯度支链三烷基苯磺酸钠的合成与表面活性

Synthesis and Surface Activity of Pure Sodium Branched Trialkylbenzenesulfonates

以短碳链烷基苯为原料,经酰化反应、格氏反应、催化加氢及磺化等六步反应合成了6种支链1,4,5 三烷基苯 3 磺酸钠,总收率均在21%以上。在烷基苯磺酸盐分子中,主链(—CHR1R2)取代在苯环的1位,短链R和R3分别取代在4位和5位。合成的三烷基苯磺酸盐的结构如下:(Ⅰ)R1=C3H7,R2=C4H9,R3=R=C2H5;(Ⅱ)R1=C4H9,R2=C4H9,R3=R=C2H5;(Ⅲ)R1=C4H9,R2=C5H11,R3=R=C2H5;(Ⅳ)R1=C3H7,R2=C4H9,R3=n C3H7,R=i C3H7;(Ⅴ)R1=C4H9,R2=C4H9,R3=n C3H7,R=i C3H7;(Ⅵ)R1=C4H9,R2=C5H11,R3=n C3H7,R=i C3H7。用1HNMR鉴定了所合成的表面活性剂的结构,用两相滴定法测定了产品中支链三烷基苯磺酸钠的质量分数均在98%以上。用表面张力法测定了30℃时它们在水溶液中的临界胶束浓度(CMC)和最低表面张力(γCMC)。6种表面活性剂的CMC(mmol/L)和γCMC(mN/m)分别为4 3,31 78(Ⅰ);4 1,31 05(Ⅱ);2 8,30 75(Ⅲ);4 0,30 85(Ⅳ);2 0,30 50(Ⅴ);1 0,30 48(Ⅵ)。

Six kinds of sodium branched 1,4,5-trialkylbenzene-3-sulfonates were synthesized through six-step process,involving Friedel-Crafts reaction,Grignard reaction,reducation and sulfonation.Short-chain alkylbenzenes were used as the starting materials.Total yields of the products were all above 21%.In the molecules of alkylbenzenesulfonates,the main chain (—CHR_1R_2) substituted at 1 position of benzene ring and two short chains(R and R_3) susbtituted at 4 and 5 positions.The structures of the trialkylbenzenesulfonates were as follows:(Ⅰ)R_1=C_3H_7,R_2=C_4H_9,R_3=R=C_2H_5;(Ⅱ)R_1=C_4H_9,R_2=C_4H_9,R_3=R=C_2H_5;(Ⅲ)R_1=C_4H_9,R_2=C_5H_(11),R_3=R=C_2H_5;(Ⅳ)R_1=C_3H_7,R_2=C_4H_9,R_3=n-C_3H_7,R=i-C_3H_7;(Ⅴ)R_1=C_4H_9,R_2=C_4H_9,R_3=n-C_3H_7,R=i-C_3H_7 and (Ⅵ) R_1=C_4H_9,R_2=C_5H_(11),R_3=n-C_3H_7,R=i-C_3H_7.The structures of these surfactants were identified by^1HNMR.The mass fractions of trialkylbenzenesulfonates in the products were all above 98%,as determined by two-phase titration.The critical micelle concentration (CMC) and the surface tension (γ_(CMC)) of six surfactants were measured at 30 ℃ in aqueous solutions.The values of CMC(mmol/L)and γ_(CMC)(mN/m) were respectively (Ⅰ) 4.3,31.78;(Ⅱ) 4.1,31.05;(Ⅲ) 2.8,30.75;(Ⅳ) 4.0,30.85;(Ⅴ) 2.0,30.50 and (Ⅵ) 1.0,30.48.