Improving the aromatic selectivity in the alkane aromatization process is of great importance for its practical utilization but challenge to make because the high H/C ratio of alkanes would lead to a serious hydrogen transfer process and a large amount of light alkanes. Herein, CO₂ is introduced into the cyclohexane conversion process on the HZSM-5 zeolite, which can improve the aromatic selectivity. By optimizing the reaction conditions, an improved aromatic (benzene, toluene, xylene, and C₉₊) selectivity of 48.2% can be obtained at the conditions of 2.7 MPa (CO₂), 450 °C, and 1.7 h⁻¹, which is better than that without CO₂ (aromatic selectivity = 43.2%). In situ transmission Fourier transform infrared spectroscopy spectra illustrate that many oxygenated chemical intermediates (e.g., carboxylic acid, anhydride, unsaturated aldehydes/ketones or ketene) would be formed during the cyclohexane conversion process in the presence of CO₂. ¹³C isotope labeling experimental results demonstrate that CO₂ can enter into the aromatics through the formation of oxygenated chemical intermediates and thereby improve the aromatic selectivity. This study may open a green, economic, and promising way to improve the aromatic selectivity for alkane aromatization process.

提高烷烃芳构化过程中的芳烃选择性对其实际应用具有重要意义，但由于烷烃的高H/C比会导致严重的氢转移过程和大量的轻质烷烃，因此实现起来具有挑战性。本文将CO ₂引入到HZSM-5沸石上的环己烷转化过程中，可以提高芳烃选择性。_{通过优化反应条件，在2.7 MPa (CO 2} )、450 ℃、1.7 h ^-1条件下，芳烃（苯、甲苯、二甲苯和C ₉₊）选择性提高到48.2% ，比没有CO ₂的情况更好（芳香族选择性= 43.2%）。原位_{透射傅立叶变换红外光谱表明，在CO 2}存在下，在环己烷转化过程中会形成许多含氧化学中间体(例如，羧酸、酸酐、不饱和醛/酮或烯酮) 。¹³ C同位素标记实验结果表明CO ₂可以通过形成含氧化学中间体进入芳烃中，从而提高芳烃选择性。该研究为提高烷烃芳构化过程的芳烃选择性开辟了一条绿色、经济且有前景的途径。