The effect of hydrogen on the number of active centers (С_Р) and the propagation rate constant (k_P) at ethylene polymerization over titanium–magnesium catalysts is studied using quenching by radioactive carbon monoxide (¹⁴СО). The polymerization rate drops after hydrogen was added to the polymerization medium mainly due to the decrease in the calculated k_P value. The changes in the polymerization rate and the experimental k_P value observed after hydrogen was added or removed are found to be reversible. The data on the effect of the [H₂]/[C₂H₄] molar ratio in the gas phase within the range of 0.125–1 on polymerization rate and the С_Р and k_P values are obtained. Reduction of the k_P value and a small decrease in the number of active centers are observed at the H₂/C₂H₄ molar ratio ≥ 0.5. These findings were used to propose a scheme interpreting the effect of hydrogen on the С_Р and k_P values. The scheme suggests that the decrease in the calculated k_P value observed in the presence of hydrogen is related to the reversible formation of temporarily inactive dormant sites containing the titanium–polymer bond.

氢对活性中心（С数量的效果_Р）和传播速率常数（k _P）在乙烯聚合过的钛-镁的催化剂是用淬火通过放射性一氧化碳（研究¹⁴ СО）。将氢添加到聚合介质中之后，聚合速率下降主要是由于所计算的k _P值的降低。发现添加或除去氢后观察到的聚合速率和实验k _P值的变化是可逆的。气相中[H ₂ ] / [C ₂ H ₄ ]摩尔比在0.125–1范围内对聚合速率和С影响的数据_获得Р和k _P值。在H ₂ / C ₂ H ₄摩尔比≥0.5时，观察到k _P值降低和活性中心数少量降低。这些发现被用来提出一个解释氢对_СР和k _P值影响的方案。该方案表明，在氢存在下观察到的k _p值的降低与含钛-聚合物键的暂时无活性的休眠位点的可逆形成有关。