Abstract

Benzyl naphthalenes are versatile compounds having multiple applications in dyes, fine chemicals, and pharmaceuticals etc. Herein, we present benzylation of naphthalene with benzyl chloride using a chloroaluminate ionic liquid which we have reported recently. The catalyst is highly active, selective and required in very low quantity i.e., 0.5% w/w to drive the reaction. The reaction was carried out at ambient temperature and pressure which has an edge over other existing catalysts that requires elevated temperature. The conversion of benzyl chloride and selectivity toward mono-benzylated product was found to be more than 95% and 90%, respectively. The formation of the product was confirmed by GC-MS. Various reaction parameters like temperature, catalyst concentration, mole ratio of benzyl chloride and naphthalene were investigated to optimize the best operating conditions to obtain the mono benzylated naphthalene. The catalyst was efficiently recyclized up to 5 times. The easy single-step synthesis of the catalysts, use of hydrophobic neutral ligand, better atom economy, makes the process more attractive for its application in benzylation reaction of naphthalene.

摘要

苄基萘是一种多用途化合物，在染料、精细化学品和药物等领域具有多种应用。在此，我们使用最近报道的氯铝酸盐离子液体将萘与苄基氯进行苄基化。该催化剂具有高活性、选择性，并且需要非常低的量，即 0.5% w/w 来驱动反应。该反应是在环境温度和压力下进行的，环境温度和压力优于其他需要高温的现有催化剂。发现苄基氯的转化率和对单苄基化产物的选择性分别超过 95% 和 90%。通过GC-MS确认产物的形成。各种反应参数，如温度、催化剂浓度、研究了苄基氯和萘的摩尔比，以优化获得单苄基萘的最佳操作条件。催化剂可有效循环使用多达 5 次。催化剂的一步合成简单、疏水性中性配体的使用、较好的原子经济性使其在萘苄基化反应中的应用更具吸引力。