Cyclopentyl methyl ether (CPME), also known as methoxycyclopentane, is a hydrophobic ether solvent. A high boiling point of 106 °C (223 °F) and preferable characteristics such as low formation of peroxides, relative stability under acidic and basic conditions, formation of azeotropes with water coupled with a narrow explosion range render CPME an attractive alternative to other ethereal solvents such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), dioxane, and 1,2-dimethoxyethane (DME).[2]
Synthesis
Cyclopentyl methyl ether is prepared by the addition of methanol to the cyclopentene catalyzed by various solid acids.
In principle it could be prepared by methylation of the cyclopentanol, but such a method is impractical.
Reactions with azeotropical removal of water: acetalization, etc.[8]
Cyclopentyl methyl ether possesses characteristics that make it a potential alternate for other ethers. According to an evaluation of three chemistry journals from 2020, ethereal solvents have a share of 22–25% of all solvents employed.[9]
In contrast to water-soluble ethers like tetrahydrofuran and 1,4-dioxane, cyclopentyl methyl ether (CPME) - being hydrophobic - acts suitably as an extractant. In aqueous phases, only trace amounts of CPME remain due to its low solubility. CPME also exhibits stability at both low and high pH levels, even under elevated temperatures and extended contact times. It can form an azeotrope with water in a ratio of 83.7% CPME to 16.3% water at an azeotropic end temperature of 83 °C.[10] These properties enable CPME to function effectively as an entrainer during esterification processes[11] and acetalizations.[12] The solvent also displays low solubility for water in CPME, reported to be 0.3 g / 100 g.[13]
^Watanabe, Kiyoshi; Yamagiwa, Noriyuki; Torisawa, Yasuhiro (February 24, 2007). "Cyclopentyl Methyl Ether as a New and Alternative Process Solvent". Org. Process Res. Dev. 11 (2): 251–258. doi:10.1021/op0680136.
^Ether compounds and polymerizable compounds and manufacturing methods. By: Kiriki, Satoshi.Aug 3, 2015.JP 2015140302
^Torisawa, Yasuhiro (15 January 2007). "Conversion of indanone oximes into isocarbostyrils". Bioorganic & Medicinal Chemistry Letters. 17 (2): 453–455. doi:10.1016/j.bmcl.2006.10.022. PMID17064893.
^Okabayashi, Tomohito; Iida, Akira; Takai, Kenta; Misaki, Tomonori; Tanabe, Yoo (September 18, 2007). "Practical and Robust Method for Regio- and Stereoselective Preparation of (E)-Ketene tert-Butyl TMS Acetals and β-Ketoester-derived tert-Butyl (1Z,3E)-1,3-Bis(TMS)dienol Ethers". The Journal of Organic Chemistry. 72 (21): 8142–8145. doi:10.1021/jo701456t. PMID17877405.
^Shimada, Toyoshi; Suda, Masahiko; Nagano, Toyohiro; Kakiuchi, Kiyomi (October 22, 2005). "Facile Preparation of a New BINAP-Based Building Block, 5,5'-DiiodoBINAP, and Its Synthetic Application". The Journal of Organic Chemistry. 70 (24): 10178–10181. doi:10.1021/jo0517186. PMID16292868.
^D. Rigo, G. Firani, A. Perosa, M. Selva (2019), "Acid-Catalyzed Reactions of Isopropenyl Esters and Renewable Diols: A 100% Carbon Efficient Transesterification/Acetalization Tandem Sequence, from Batch to Continuous Flow", ACS Sustainable Chem. Eng., vol. 7, no. 23, pp. 18810–18818, doi:10.1021/acssuschemeng.9b03359{{citation}}: CS1 maint: multiple names: authors list (link)
^U. Azzena, M. Carraro, A.D. Mamuye, I. Murgia, L. Pisano, G. Zedde (2015), "Cyclopentyl methyl ether–NH4X: a novel solvent/catalyst system for low impact acetalization reactions", Green Chem., vol. 17, no. 6, pp. 3281–3284, doi:10.1039/C5GC00465A{{citation}}: CS1 maint: multiple names: authors list (link)
^U. Azzena, M. Carraro, L. Pisano, S. Monticelli, R. Bartolotta, V. Pace (2019), "Cyclopentyl Methyl Ether: An Elective Ecofriendly Ethereal Solvent in Classical and Modern Organic Chemistry", ChemSusChem, vol. 12, no. 1, pp. 40–70, doi:10.1002/cssc.201801768, PMC6391966{{citation}}: CS1 maint: multiple names: authors list (link)
