Journal of Molecular Catalysis A: Chemical 253 (2006) 16–19 Short communication H 14 [NaP 5 W 30 O 110 ]: A heteropoly acid catalyzed acetylation of alcohols and phenols in acetic anhydride Majid M. Heravi a,∗ , Farahnaz K. Behbahani b , Fatemeh F. Bamoharram a a Department of Chemistry, School of Sciences, Azzahra University, Vanak, Tehran, Iran b Department of Chemistry, Islamic Azad University, Mashhad Branch, Mashhad, Iran Received 25 January 2006; received in revised form 20 February 2006; accepted 21 February 2006 Available online 4 April 2006 Abstract A trace amount of H 14 [NaP 5 W 30 O 110 ] (0.1 mol%) has been effectively used as heteropoly acid catalyst for acetylation of alcohols and phenols with acetic anhydride at room temperature. © 2006 Elsevier B.V. All rights reserved. Keywords: H 14 [NaP 5 W 30 O 110 ]; Acetylation; Acetic anhydride; Alcohols; Phenols 1. Introduction Acetylation of hydroxyl groups is one of the most frequently used transformations in organic synthesis. Among the various protecting groups used for the hydroxyl function, acetyl is the most common group in view of its easy introduction, being stable to the acidic reaction conditions, and also easily removable by mild alkaline hydrolysis [1]. The most commonly used reagent combination for this reaction uses acid anhydride in the presence of acid or base catalysts [2]. Various metal salts such as CoCl 2 [3], TiCl 4 –AgClO 4 [4], Me 3 SiCl [5], LiClO 4 [6], Mg(ClO 4 ) 2 [7] and some metal triflates such as Se(OTf) 3 [8] MeSiOTf [9], In(OTf) 3 [10], Cu(OTf) 2 [11] and Bi(OTf) 3 [12] have been investigated to meet the demand for more efficient and selective methods. In spite of these waves of interest due to the importance of acetylation, introduction of inexpensive and green catalyst for this purpose is still in much demand. Development of methods using heteropoly acids (HPAs) as catalysts for fine organic synthetic processes related to fine chemicals, such as flavors, pharmaceuticals and food industries [13] have been under attention in the last decade. Heteropoly acids are more active catalysts than conventional inorganic and organic acids for various reactions in solution [14]. They are used as industrial catalysts for several liquid-phase reactions [15–18], ∗ Corresponding author. Tel.: +98 9121329147; fax: +98 218047861. E-mail address: mmh1331@yahoo.com (M.M. Heravi). such as alcohol dehydration [19], alkylation [20], or esterifica- tion [21] reactions. Among heteropoly acids, polytungstic acids are the most widely used catalysts owing to their high acid strengths, thermal stabilities and low reducibilities. The cat- alysts based on heteropoly acids have many advantages over liquid acid catalysts. They are not corrosive and environmentally benign, presenting fewer disposal problems. Solid heteropoly acids have attracted much attention in organic synthesis owing to easy workup procedures, easy filtration, and minimization of cost and waste generation due to reuse and recycling of the catalysts [22]. 2. Results and discussion Recently, we described acetylation of alcohols and phenols [23] and direct acetylation of tetrahydropyranyl ethers [24] by ferric perchlorate and acetylation of THP ethers by bismuth nitrate [25]. In continuation with our work using heteropoly acids [26] which are low in toxicity, highly stable towards humid- ity, being recyclable and air stable, we found that a trace of H 14 [NaP 5 W 30 O 110 ] (0.1 mol%) is able to promote quantitative acetylation of alcohols and phenols using acetic anhydride as acetylating agent, at room temperature, in high yields and short reaction time in solvent free conditions with a simple method and easy workup procedure (Scheme 1; Table 1). In order to extend the scope of this acetylation reaction, it was carried out on a variety of substrates using a typ- 1381-1169/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.molcata.2006.02.057