Mechanochemical Dechlorination of Trichlorobenzene on Oxide Surfaces

Abstract

1,2,3-Trichlorobenzene (TCB) was ground with calcium oxide (CaO) powder in air with a planetary ball mill. A mechanochemical reaction was induced, resulting in the decomposition of TCB through dechlorination from the benzene nucleus. The mechanochemical dechlorination was monitored by a suite of analytical methods including X-ray diffraction (XRD), thermogravimetry (TG), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, electron spin resonance (ESR), gas chromatography/mass spectrometry (GC/MS), and ion chromatography. With the increase in grinding time, the remaining amount of TCB decreased and reached 0.02% at 360 min grinding. On the other hand, the water-soluble amount of chlorine increased correspondingly and reached 95%, indicating the successful transformation of chlorine from organics into inorganic chloride. Additionally, the other final products detected after grinding were carbon and some minor methane and ethane, although the formation of some chlorine-containing intermediate phases such as dichlorobenzene and tetrachlorobenzene was observed in the early stage of grinding (for 1 h). A possible decomposition pathway based on dechlorination or dehydrochlorination is compared.

Decomposition of hexachlorobenzene over Al2O3 supported metal oxide catalysts

“…These complex and poorly understood surfaces usually lead to a variety of chemical interaction pathways. Tanaka (2003) reported that the mechanochemical decomposition of trichlorobenzene on CaO was not dehydrochlorination but dechlorination; similar conclusion was also drawn by Krishnamoorthy (2000). However, the oxidation process also existed during the decomposition of chlorinated aromatic compounds.…”

Mechanochemical degradation of hexachlorobenzene using Mg/Al2O3 as additive

“…Other study also presented similar results. Yasumitsu et al [30] used calcium oxide as additive to destruct 1,2,3-Trichlorobenzene (TCB) by ball milling, and found that the final products contained some minor methane and ethane except carbon after 360 min milling. Loiselle et al [21] also detect methane and ethane in the end products during the process of mechanochemical treatment of chlorobenzenes.…”

A Method of Monitoring Explosive Under Cyclic Mechanical Stress

“…[1,2,3,4] Ball mills provide one of the most common tools for mechanical stimulation of solid state processes such as phase transitions, [5,6,7] solid-solid reactions [8,9,10,11,12] decompositions, [13,14] as well as degradation [15,16,17] and amorphization [18] of polymers. Ball mills are capable of producing high strain fields that allow for initiating the aforementioned processes without heating.…”