Thermal Degradation Characteristics of Carbon Tetrachloride in Excess Hydrogen Atmosphere

과잉수소 반응조건하에서 사염화탄소의 고온 분해반응 특성 연구

  • Won, Yang-Soo (Department of Environmental Engineering, Yeungnam University) ;
  • Jun, Kwan-Soo (Department of Environmental Engineering, Yeungnam University) ;
  • Choi, Seong-Pil (Department of Environmental Engineering, Yeungnam University)
  • Published : 1996.10.01

Abstract

pure compound chloromethanes; methyl chloride, methylene chloride, chloroform and The carbon tetrachloride were used as a model of chlorocarbon system with Cl/H ratio to investigate thermal stability and hydrodechlorination process of carbon tetrachloride under excess hydrogen atmosphere. The parent thermal stability on basis of temperature required for 99% destruction at 1 second no was evaluated as $875^{\circ}C$ for $CH_3Cl$, $780^{\circ}C$ for $CH_2Cl_2$, $675^{\circ}C$ for $CHCl_3$ and $635^{\circ}C$ for $CCl_4$. Chloroform was thermally less stable than $CCl_4$ at fairly low temperatures $(<570^{\circ}C).$ The lion of $CCl_4$ became more sensitive to increasing temperature, and $CCl_4$ was degraded CHCl3 at above $570^{\circ}C.$ The number and quantity of chlorinated products decreases with increasing temperature for the Product distribution of $CCl_4$ decomposition reaction system. Formation of non-chlorinated hydrocarbons such as $CH_4$, $C_2H_4$ and C_2H_6$ increased as the temperature rise and particularly small amount of methyl chloride was observed above $850^{\circ}C$ in $CC1_4$/$H_2$ reaction system. The less chlorinated products are more stable, with methyl chloride the most stable chlorocarbon in this reaction system.

과잉수소 반응조건하에서 사염화탄소의 열적 안정성과 수첨탈염소화 과정을 고찰하기 위한 모델로써 Cl/H의 비가 다른 순수 염화메탄화합물인 메틸염소, 메틸렌염소, 클로로포름과 사염화탄소를 이용하였다. 반응시간 1초에서 99% 분해되는 온도를 기준으로한 열적 안정성은 메틸염소는 $875^{\circ}C,$ 메틸렌염소는 $780^{\circ}C,$ 클로로포름은 $675^{\circ}C,$ 사염화탄소는 $635^{\circ}C$ 이었으며, 낮은 반응온도영역에서는 클로로포름의 열적 안정성이 사염화탄소보다 낮았으나 온도가 증가함에 따라 사염화탄소의 분해가 증가하여 $570^{\circ}C$ 이상에서는 클로로포름보다 쉽게 분해되었다. 사염화탄소의 분해 반응계에서의 생성물 고찰결과, 반응온도가 증가함에 따라 염화탄화수소 화합물 계열 생성물의 농도와 염화정도가 감소하였다. 과잉수소 반응조건에서 사염화탄소 열분해 실험결과, $850^{\circ}C$ 이상에서는 탈염소화 탄화수소화합물인 메탄, 에틸렌, 에탄의 생성물의 농도가 증가하였으며 염소화 합물로는 메틸염소만이 소량 검출되었다. 이는 염화정도가 낮은 화합물일수록 열적 안정성이 크다는 것을 의미하며 CCl4/H2 반응계에서 염화탄소화합물중 메틸염소가 열적 안정성이 가장 큰 화합물이었다.

Keywords

References

  1. Thermochemical Kinetics Benson,S.W.
  2. 11th Symposium (international) on combustion Application of very low pressure pyrolysis to combustion kinetics Benson,S.W.;Spokes,G.N.
  3. Environ. Sci. & Tech. v.20 Conversion of chloroform to HCI by reaction with hydrogen and water vapor Chuang,S.C.;Bozzelli,J.W.
  4. NSRDS-NBS 31 Darwent,B.deB.
  5. J.Chem.Phys. v.79 no.4 Infrared laser multiple photon dissociation of CDCl₃in a molecular beam Herman,I.P.;Magnotta,F.;Buss,R.J.;Lee,Y.T.
  6. chloroform J.Org.Chem. v.29 Reaction of cyclohexene with a thermal dichlorocarbene Kung,F.E.;Bissinger,W.E.
  7. US.EPA 600/2.79.198, NTIS PB 80-131964 Mason,L.;Unget,S.
  8. J.Phys.Chem. v.97 no.9 Thermal decomposition of carbon tetrachloride Michael,J.V.(et al.)
  9. Ber.Bunsenges Phys.Chem. v.83 Schung,K.P.;Wagner,H.G.;Zabel,F.
  10. J.Phys.Chem. v.87 no.2 Heat of formation of the CHCl₂radical bond dissociation energies in chloromethanes of chloroethanes Weissman,M.;Benson,S.W.
  11. Combust. Sci. Tech. v.85 Chloroform pyrolysis : Experiment and detailed reaction model Won,Y.S.;Bozzelli,J.W.
  12. J.Korean Soc.Environ.Eng. v.17 no.2 Pyrolytic reaction pathway of chloroform with excess hydrogen Won,Y.S.;Choi,S.P.