Cyclopentyl methyl ether
{{chembox
| Watchedfields = changed
| verifiedrevid = 417919604
| Name = Cyclopentyl methyl ether
| ImageFile = CPME.svg
| ImageSize = 150px
| ImageName = Chemical structure of cyclopentyl methyl ether
| PIN = Methoxycyclopentane
| OtherNames = CPME
|Section1={{Chembox Identifiers
| SMILES = COC1CCCC1
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 122157
| InChI = 1S/C6H12O/c1-7-6-4-2-3-5-6/h6H,2-5H2,1H3
| InChIKey = SKTCDJAMAYNROS-UHFFFAOYSA-N
| CASNo = 5614-37-9
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 4067E5GBKB
| PubChem = 138539
| EINECS = 445-090-6
}}
|Section2={{Chembox Properties
| C=6|H=12|O=1
| Appearance = Colorless clear liquid
| Solubility = 0.011 g/g
| MeltingPtC = -140
| BoilingPtC = 106
}}
|Section7={{Chembox Hazards
| ExternalSDS = [http://datasheets.scbt.com/sc-252651.pdf MSDS]
| GHSPictograms = {{GHS02}}{{GHS07}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|225|302|312|315|319}}
| PPhrases = {{P-phrases|210|233|240|241|242|243|264|270|280|301+312|302+352|303+361+353|305+351+338|312|321|322|330|332+313|337+313|362|363|370+378|403+235|501}}
| NFPA-H = 2
| NFPA-F = 3
| NFPA-R = 0
| FlashPtC = -1
}}
}}
Cyclopentyl methyl ether (CPME), also known as methoxycyclopentane, is a hydrophobic ether solvent. A high boiling point of {{convert|106|C|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).{{cite journal|date=February 24, 2007|title=Cyclopentyl Methyl Ether as a New and Alternative Process Solvent|journal=Org. Process Res. Dev.|pages=251–258| doi = 10.1021/op0680136|volume=11|issue=2|last1=Watanabe|first1=Kiyoshi|last2=Yamagiwa|first2=Noriyuki|last3=Torisawa|first3=Yasuhiro}}
Synthesis
Cyclopentyl methyl ether is prepared by the addition of methanol to the cyclopentene catalyzed by various solid acids.
: 400px
In principle it could be prepared by methylation of the cyclopentanol, but such a method is impractical.
Applications
Cyclopentyl methyl ether could as a solvent for extraction, polymerization, crystallization and surface coating.
Some examples of reactions where it acts as a solvent are:
- Reactions involving alkali agents: nucleophilic substitutions of heteroatoms (alcohols and amines) Ether compounds and polymerizable compounds and manufacturing methods. By: Kiriki, Satoshi.Aug 3, 2015.JP 2015140302
- Lewis acids-mediated reactions: Beckmann Reaction, Friedel-Crafts Reaction etc.{{cite journal|last1=Torisawa|first1=Yasuhiro|title=Conversion of indanone oximes into isocarbostyrils|journal=Bioorganic & Medicinal Chemistry Letters|date=15 January 2007|volume=17|issue=2|pages=453–455|doi=10.1016/j.bmcl.2006.10.022|pmid=17064893}}
- Reactions using Organometallic reagents or basic agents: Claisen condensation, formation of enolates or Grignard reaction.{{cite journal|last1=Okabayashi|first1=Tomohito|last2=Iida|first2=Akira|last3=Takai|first3=Kenta|last4=Misaki|first4=Tomonori|last5=Tanabe|first5=Yoo|title=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|journal=The Journal of Organic Chemistry|date=September 18, 2007|volume=72|issue=21|pages=8142–8145|doi=10.1021/jo701456t|pmid=17877405}}
- Reduction and oxidation.{{cite journal|last1=Shimada|first1=Toyoshi|last2=Suda|first2=Masahiko|last3=Nagano|first3=Toyohiro|last4=Kakiuchi|first4=Kiyomi|title=Facile Preparation of a New BINAP-Based Building Block, 5,5'-DiiodoBINAP, and Its Synthetic Application|journal=The Journal of Organic Chemistry|date=October 22, 2005|volume=70|issue=24|pages=10178–10181|doi=10.1021/jo0517186|pmid=16292868}}
- Reactions with transition metal catalysts.{{cite journal|last1=Molander|first1=Gary A.|last2=Elia|first2=Maxwell D.|title=Suzuki−Miyaura Cross-Coupling Reactions of Benzyl Halides with Potassium Aryltrifluoroborates|journal=The Journal of Organic Chemistry|date=November 3, 2006|volume=71|issue=24|pages=9198–9202|doi=10.1021/jo061699f|url= |pmid=17109547|pmc=2515367}}
- Reactions with azeotropical removal of water: acetalization, etc.{{cite journal|last1=Azzena|first1=Ugo|last2=Carraro|first2=Massimo|last3=Mamuye|first3=Ashenafi Damtew|last4=Murgia|first4=Irene|last5=Pisano|first5=Luisa|last6=Zedde|first6=Giuseppe|title=Cyclopentyl methyl ether – NH4X: a novel solvent/ catalyst system for low impact acetalization reactions|journal=Green Chemistry|date=17 April 2015|volume=17|issue=6|pages=3281–3284|doi=10.1039/c5gc00465a}}
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.{{citation|author=A. Jordan, C.G.J. Hall, L.R. Thorp, H.F. Sneddon|date=2022|doi=10.1021/acs.chemrev.1c00672|pages=6749–6794|periodical=Chem. Rev.|title=Replacement of less-preferred dipolar aprotic and ethereal solvents in synthetic organic chemistry with more sustainable alternatives|volume=122|pmc=9098182}}
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.{{cite web|access-date=2022-10-20|date=June 2018|format=PDF|publisher=Zeon Corporation|title=Novel hydrophobic ether solvent – Cyclopentyl methyl ether – CPME – Technical Data|url=https://www.zeon.co.jp/en/business/enterprise/special/solvent-cpme/pdf/000084448.pdf}} These properties enable CPME to function effectively as an entrainer during esterification processes{{citation|author=D. Rigo, G. Firani, A. Perosa, M. Selva|date=2019|doi=10.1021/acssuschemeng.9b03359|issue=23|pages=18810–18818|periodical=ACS Sustainable Chem. Eng.|title=Acid-Catalyzed Reactions of Isopropenyl Esters and Renewable Diols: A 100% Carbon Efficient Transesterification/Acetalization Tandem Sequence, from Batch to Continuous Flow|volume=7}} and acetalizations.{{citation|author=U. Azzena, M. Carraro, A.D. Mamuye, I. Murgia, L. Pisano, G. Zedde|date=2015|doi=10.1039/C5GC00465A|issue=6|pages=3281–3284|periodical=Green Chem.|title=Cyclopentyl methyl ether–NH4X: a novel solvent/catalyst system for low impact acetalization reactions|volume=17}} The solvent also displays low solubility for water in CPME, reported to be 0.3 g / 100 g.{{Cite web |title=Zeon Corporation |url=https://www.zeon.co.jp/business_e/enterprise/spechemi/cpme_tec_sup_e_200906.pdf |url-status=dead |archive-url=https://web.archive.org/web/20110722102229/http://www.zeon.co.jp/business_e/enterprise/spechemi/cpme_tec_sup_e_200906.pdf |archive-date=2011-07-22 |access-date=2024-08-05 |website=}}
Cyclopentyl methyl ether is touted as an eco-friendly solvent in a wide range of still other processes, such as reductions, oxidations, and Grignard reactions.{{cite web|access-date=2022-10-20|date=September 2018|format=PDF|language=en|publisher=Zeon Corporation|title=Synthetic Applications with Cyclopentyl methyl ether (CPME), Ver. 2.0|url=https://www.zeon.co.jp/en/business/enterprise/special/solvent-cpme/pdf/000204797.pdf}}{{citation|author=U. Azzena, M. Carraro, L. Pisano, S. Monticelli, R. Bartolotta, V. Pace|date=2019|doi=10.1002/cssc.201801768|issue=1|pages=40–70|periodical=ChemSusChem|title=Cyclopentyl Methyl Ether: An Elective Ecofriendly Ethereal Solvent in Classical and Modern Organic Chemistry|volume=12|doi-access=free|pmc=6391966}}