Alkylbenzyl Polyoxyethylene Ethers Derived From Alkylbenzene: A Synthesis Investigation

Alkylphenol ethoxylates(APEO) is one of the most important raw materials in dyeing and printing auxiliary. Because of the advantages of being insensitive about acid and base, being stable and being cheap, APEO has been a kind of surfactants added in dyeing and printing textile. The benzyl structure can smooth the pola rity between hydrophobic group and hydrophilic group, thus APEO has good emulsification, solubilizing, wetting, permeability, dispersion force and detergence and was widely applied in the fields of fine chemicals, drugs and polymers. However, many EU countries prohibit the use of APEO as the biodegradability and toxicity of APEO and environmental hormones and toxicity of its degradation products have attracted widespread attention in recent years. Along with the awareness of environmental security growing, comprehensive restrictions on the use of APEO are becoming an inevitable trend. Therefore, to find an alternative of APEO to retain excellent properties brought by the structure of benzene ring and avoid the biodegradability and toxicity caused by alkylphenol is of important significance. Alkyl benzyl polyoxyethylene ethers owning the similar structure with APEO but no phenol structure, making it possible to be an effective alternative of APEO. The reaction scheme of dodecylbenzyl polyoxyethylene prepared from dodecylbenzene, a cheap and commonly available bulk chemical raw materials, through chlorine methylation, hydroxylation and ethoxylates will be explored in this article.Two chloromethylation reaction routes were explored in this article. The first route is using ionic liquid to catalyze the reaction; the second is carried by in-situ generating hydrogen chloride gas. A waterproof ionic liquid [Bz Mim][BF4] was designed for catalytic reaction in which hydrogen chloride gas generated from traditional Blanc chloromethylation reaction was replaced with concentrated hydrochloric acid; and the ionic liquid presents the similar structure with the materials and the product, which may increase its affinity for the raw material and the product, thus improve the co nversion rate and selectivity of the reaction. With the chloromethylation of toluene as a model reaction, chloromethylation catalyzed by [Bz Mim][BF4] was explored for its feasibility. The results showed that when the molar ratio of [Bz Mim][BF4] to toluene, paraformaldehyde to toluene and concentrated hydrochloric acid to toluene were seperately 0.3, 1.3 and 7.5, the reaction temperature was 80 oC, the reaction time was 8 h, the yield of chloromethylation reached the highest by 88.5%. However, the catalytic effect of [Bz Mim][BF4] in the chloromethylation reaction of industrial- grade linear dodecylbenzene was absent, chloromethylation of dodecylbenzene did not occur.Hydrogen chloride gas can also be avoided to use in the chloromethylation of dodecylbenzene by exploring a new method of in-situ generating hydrogen chloride. With chloromethylation of dodecylbenzene as the first model reaction, the results showed that when the reaction temperature was 90 oC, the reaction time was 5 h, the molar ratio of paraformaldehyde to sodium dodecyl benzene was 2 : 1, the reaction yield reached 75%. With the chloromethylation of industrial-grade linear dodecylbenzene as the second model reaction, the expected product dodecyl benzyl chloride was also produced, indicating that it is feasible for the chloromethylation of dodecyl benzene in this way.Two hydroxylation reaction routes direct hydrolysis and after-esterification hydrolysis of dodecyl benzyl chloride were explored in this article. The hydroxylation of dodecyl benzyl chloride was studied according to the method for the hydrolysis of short-chain alkyl benzyl chloride reported in the literature. The results showed that the hydrolysis reaction does not occur according to structural characterization of the product. Dodecyl benzyl chloride was hydroxylated by consulting the methods reported for the hydrolysis of short-chain alkyl benzyl chloride and long-chain alkyl benzyl bromide after esterification. The expected dodecyl benzyl alcohol was proved prepared according to the structural characterization, which indicated that it can be successfully hydroxylated for the hydrolysis after esterification of dodecyl benzyl chloride. And a series of dodecyl benzyl polyoxyethylene ethers with different degrees of polymerization were synthesized from dodecyl benzyl alcohol reacting with different molar ratios of ethylene oxide and their performance were also tested. The results showed that the cloud point increased, the emulsifying power decreased, the solubilizing power increased and the critical micelle concentration(cmc) decreased when the number of EOs in dodecyl benzyl polyoxyethylene ethers increased above 9. Compared with the most common alkylphenol ethoxylates TX-10, dodecyl benzyl polyoxyethylene with 9 EOs present the similar clo ud point, emulsifying power, solubilizing power and cmc and may be an effective alternative to TX-10.In this work, the feasibility of chloromethylation reaction, hydroxylation reaction and ethoxylation reaction. Compared the products property to TX-10, the result shows that the linear alkyl benzyl alcohol polyoxyethylene ether with 9 EOs has a similar cloud point,emulsifying ability, solubilizing and cmc, and can be a effective replacement of TX-10.