Sustainable xylene production via CO₂-driven methylation of benzene and toluene for carbon-neutral aromatics

The selective conversion of CO₂ into value-added aromatics, specifically xylenes, offers a promising strategy for both carbon emission reduction and the sustainable production of industrially important chemicals. Among these, the alkylation or methylation of benzene and toluene to produce xylenes in the presence of CO₂ has attracted considerable attention due to its potential to integrate CO₂ utilization with aromatic upgrading. This review provides a comprehensive overview of recent advances in this field, such as thermodynamic analyses and detailed mechanistic insights into both indirect and direct alkylation pathways. The development of catalysts that integrate active metal oxides for CO₂ hydrogenation with acidic zeolites for selective alkylation/methylation is discussed. Strategies for tuning catalytic properties to enhance performance are also highlighted. The key factors in critical catalyst design that influence catalytic performance, such as active metal oxides, oxygen vacancies, zeolite topology, and acid site distribution, are discussed in detail. Additionally, reaction parameters such as temperature, pressure, feed composition, space velocity, metal-zeolite proximity, and catalyst mass ratio significantly impact the catalytic performance. Challenges associated with catalyst deactivation, undesired side reactions, reaction selectivity, and long-term stability are also critically assessed. Finally, emerging strategies and prospects for designing robust, highly selective, and industrially viable catalyst systems are discussed. This review aims to provide valuable guidance for advancing CO₂-driven alkylation/methylation processes toward sustainable xylene production and carbon-neutral aromatics synthesis.