than tetra penta or hexachlorinated m xylenes which cannot be recycled this can be attained by maintaining the temperature of m xylene between about 100 u00b0 c to 130 u00b0 c at atmospheric pressure and slowly introducing chlorine gas under ultraviolet irradiation through the liquid on startup or for batch processing this is continued until approximately 3 moles of chlorine per mole of xylene have been absorbed at this point the reaction mixture will contain about 35 45 mole per cent preferably about 40 mole of the desired u03b1 u03b1 u03b1 39 trichloro m xylene cmbc upon completion of the reaction the mixture is distilled and the lighter fractions less than trichlorinated are recycled during chlorination of these recycled lighter fractions which have been added to xylene chlorine is added until about 1 9 moles of chlorine mole xylene have been absorbed again corresponding to formation of about 35 45 mole per cent preferably about 40 mole of cmbc in the reaction mixture the u03b1 u03b1 u03b1 39 trichloro m xylene cmbc may be distilled and obtained in a purity of greater than 90 in a particularly preferred embodiment of this step the u03b1 u03b1 u03b1 39 trichloro m xylene cmbc is not distilled but carried forward as a crude material ca 70 purity to the next steps the recycle of underchlorinated material thus minimizing chlorine and xylene consumption and production of wastes and the avoidance of elaborate distillation are particular advantages of this process in the second step.