去除三氯氢硅（SiHCl₃）中的碳杂质可提高多晶硅的纯度，但SiHCl₃和二甲基一氯硅烷［（CH₃）₂SiHCl］的沸点极为接近，在精馏过程中易形成共沸物。因此，SiHCl₃中的（CH₃）₂SiHCl较难去除。提出以Cl₂为氯源，通过热氯化反应将（CH₃）₂SiHCl转化为高沸点的甲基氯硅烷，以增大相对挥发度，便于后续精馏除杂。但（CH₃）₂SiHCl和SiHCl₃会同时发生氯化反应，为此，探究了两者转化率随温度的变化。结果表明，在60 ℃、120 min时，（CH₃）₂SiHCl的转化率为53.1%，SiHCl₃的转化率为14.3%，（CH₃）₂SiHCl的转化率最佳。最后，通过密度泛函理论计算分析了反应路径，确定了反应机理。SiHCl₃、（CH₃）₂SiHCl氯化反应的能垒差在于Cl₂与SiCl₃·、（CH₃）₂SiCl·反应的能垒，且Cl₂与SiCl₃·反应的能垒比与（CH₃）₂SiCl·反应的能垒高60.4 kJ/mol。

Removal of carbon impurities from trichlorosilane（SiHCl₃） can improve the purity of polysilicon.However，the points of chlorodimethylsilane［（CH₃）₂SiHCl］ and SiHCl₃ are very close，and azeotrope is easily formed in the distillation process.Therefore，（CH₃）₂SiHCl in SiHCl₃ is difficult to remove.It was proposed to use Cl₂ as the chlorine source to convert（CH₃）₂SiHCl into high boiling methyl chlorosilane through thermal chlorination reaction to increase the relative volatility and facilitate the distillation.However，SiHCl₃ and（CH₃）₂SiHCl were chlorinated at same time.Therefore，the change of the conversion of the two with temperature was investigated.The results showed that the conversions of（CH₃）₂SiHCl and SiHCl₃ were 53.1% and 14.3% at 60 ℃ and 120 min，and the selectivity of（CH₃）₂SiHCl was the best.Finally，the reaction path was calculated and analyzed by density functional theory，and the reaction mechanism was determined.The difference between the reactions of SiHCl₃ and（CH₃）₂SiHCl resulted from the different energy barriers for the reactions of the SiCl₃· and（CH₃）₂SiCl· radicals with Cl₂.The energy barrier of the reaction of SiCl₃· with Cl₂ was 60.4 kJ/mol higher than that of the reaction of（CH₃）₂SiCl·.