通过分子动力学模拟, 探讨了乙炔高温热解制备富勒烯的可能条件. 结果显示, 乙炔裂解可以形成富勒烯. 在裂解过程中, 乙炔热解产生的氢原子和氢分子能起到球磨碳团簇和阻止其尺寸过度增长的作用, 并促使碳笼更趋近于经典富勒烯, 暗示从炔烃制备富勒烯不需要惰性气体的协助, 从而可显著降低富勒烯的生产成本. 模拟显示, 以乙炔为反应物时, 主要有两种途径形成富勒烯. 第一种是碳链→团簇→碳笼, 多发生于低密度条件下; 第二种是碳链→团簇→碳片→碳笼, 多发生于高密度条件下. 在富勒烯形成过程中, 六元环的增长是由碳笼缺陷和键的旋转导致的. 这些结果有助于理解从炔烃热解制备富勒烯的过程, 对开发富勒烯的低成本生产方法具有重要启示意义.

Acetylene (C₂H₂) is one of the main intermediate species in the industrial conversion of natural gas to many high-value chemicals. In this work, molecular dynamics simulation was carried out to study the possibility of producing fullerenes by high temperature pyrolysis of acetylene. The effect of atomic and molecular hydrogen, reaction temperature and carbon density were discussed according to the results obtained from reactive force filed molecular dynamics simulation. The results show that C₂H₂ can form fullerenes at suitable temperature and density. In the early stage, hydrogen in the system is conducive to the aggregation of small carbon clusters and the formation of carbon chains is faster. Interestingly, in the later stage, it is not conducive to further aggregation reaction, but the atomic and molecular hydrogen produced by C₂H₂ pyrolysis can make the carbon clusters rounder and prevent the excessive growth of the carbon clusters, and can make the carbon cage more similar to classical fullerenes, which suggest that the production of fullerenes from C₂H₂ does not require the assistance of inert gases, thus significantly reducing the production cost of fullerenes in principle. Two main pathways of fullerenes formation were observed in simulations under different conditions. The first pathway is from carbon chain, cluster to carbon cage, most occurring in low density conditions. The other pathway is from carbon chain, cluster, graphene and carbon cage, most occurring in high density conditions. The growth of six-membered rings during fullerene formation is realized mainly via carbon cage defects and bond rotation, and the general trend is to make the carbon cage closer to the classical fullerene. The preparation of fullerenes by C₂H₂ pyrolysis is worthy of further study. These results are helpful to understand the process of producing fullerenes from the pyrolysis of C₂H₂ and have important implications for the development of industrial production methods of fullerenes.