Photocatalytic Reduction Of 6-Chloro-3-nitrotoluene-4-sulfonic Acid With Nanometer Particle

6-Chloro-3-nitrotoluene-4-sulfonic acid (CNSA) is a widely used intermediate for organic pigment. In industry its nitro-group is commonly reduced with Fe powder which can cause severe damage to the environment. Hence, the photocatalytic reduction is believed to present many advantages due to the fact that the UV light and TiO₂ are both clean and atoxic. The present study investigated the photocatalytic reduction of CNSA in the presence of TiO₂ under UV irradiation. It is the first time that bi-component has been taken into consideration on the photocatalytic reduction of nitro compound. Our main purpose is to examine how the presence of surfactants and organic additives affect the photoassisted reduction of CNSA as well as the adsorption model between substrate and catalyst in TiO₂ suspensions.The mixture of CNSA, TiO₂, water, additives and surfactants was added to a quartz glass reactor with a jacket though which cool water ran. After stirred for 20 min in the dark, the mixture was irradiated with a high pressure Hg lamp in the purging of nitrogen gas.The photocatalytic reduction conversion of CNSA is enhanced after the addition of DBS (sodium dodecylbenzenesulfonate) in the presence of methanol, DMF and formaldehyde. Similarly, the higher concentration of SDS (sodium dodecylsulfate) adopted the higher conversion value of CNSA reached. As for CTAB, the photocatalytic reaction is suppressed to some extent. The variation of OP-10 concentration doesn't accelerate the reaction obviously. In the system containing methanol, surfactants can promote the reaction in the order of: DBS > CTAB (cetyltrimethylammonium bromide) > SDS > OP-10 (p-nonylphenyl polyoxyethylene ethers). In most cases, surfactants under 1cmc (critical micelle concentration) lead to the highest reduction conversion followed by 10cmc and 0.1cmc. The effect of organic additives on the conversion of CNSA is as follows: methanol > DMF > acetonitrile > formaldehyde. The adsorption ability of CNSA onto the semiconductor is of particular importance. The reduction efficiency is negatively correlated to CNSA adsorption without methanol while shows positive relation in the presence of methanol for each system containing DBS, CTAB and OP-10, respectively.