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sustainability / green chemistry Industry perspective

Shunji Sakamoto Contribution of Cyclopentyl Methyl (CPME) to Green Chemistry

S hUNJI SAKAMOTO Specialty Chemicals Division, ZEON CORPORATION, 1-6-2 Marunouchi, Chiyoda-ku, Tokyo, 1008246, Japan

easy peroxide formation and water miscibility, the demand KEYWORDS for CPME has steadily been growing in the pharmaceutical , CPME, Green Chemistry, industry as well as in the electronic and fragrance , process, ICH. industries. Also, CPME has been registered or listed in the corresponding legislations for new chemical substances of United States of America, Canada, European Union, ABSTRACT Japan, South Korea, China and Chinese Taipei, and is commercially available in these countries and regions as Cyclopentyl methyl ether (CPME) is an alternative well as others including India. solvent and has preferable properties including higher In this article, I answer the question why CPME is “Green” hydrophobicity, lower formation of peroxides and better even though it is derived from petroleum. stability under acidic and basic conditions compared to other traditional ether such as tetrahydrofuran. Due to the above unique properties, CPME has particular UNIQUE FEATURES OF CPME 24 advantages and renders some conventional reaction sequences in one pot or easier process as a result of CPME is an asymmetric aliphatic ether having a cyclopentyl solvent unification and facile isolation of the products, group. It has seven unique features attributed to its structure which contribute to Green Chemistry as well as to (Table 1). process innovation. CPME meets eight definitions out of the 12 Principles of Green Chemistry (1) because of Extremely lower miscibility with water the above characteristics as well as its manufacturing The solubility of CPME in water is only 1.1% and that of water process and its applications. in CPME is also only 0.3% (23°C) (2), which gives a very clear separation of organic and water phases and an easy recovery. This immiscibility with water of CPME allows its use as a reaction solvent and extraction solvent as well as a crystallization solvent. INTRODUCTION Lower formation of peroxides n the recent process chemistry for pharmaceutical and The formation of peroxides in CPME is much lower and slower other fine chemical industries, scientists’ demand for than that of other such as MeTHF, IPE and THF (Figure 1). Igreener solvents has been increasing day by day. In view of the circumstances, typical ether solvents, such as tetrahydrofuran (THF), 2-methyl tetrahydrofuran (MeTHF), Diisopropylether (IPE), 1,4-dioxane and methyl t-butyl ether (MTBE), have some inherent properties which are incompatible with Green Chemistry. For example, THF easily forms explosive peroxides (2) and is difficult to recover because of its infinite miscibility with water. MeTHF is the unrivaled replacement for THF because of its high solvency and low miscibility with water as well as renewability (3). However, it generates more peroxides than THF (Figure 1) and is still soluble in water at 14 wt% (20°C) (3). In November, 2005, Cyclopentyl methyl ether (CPME) was commercialized by ZEON CORPORATION with its unique C5 feedstock and synthetic technologies. CPME has been found to be an alternative solvent and has many preferable characteristics for Green Figure 1. Peroxide formation of ethereal solvents Chemistry. Because it is free of drawbacks including

Chimica Oggi - Chemistry Today - vol. 31(6) November/December 2013