Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/15/2004
Publication Date: 4/1/2004
Citation: Kenar, J.A., Knothe, G.H., Copes, A.L. 2004. Synthesis and characterization of dialkyl carbonates prepared from mid-, long-chain, and guerbet alcohols. Journal of the American Oil Chemists' Society. 81(3):285-291. Interpretive Summary: Currently, interest in longer-chain and branched compounds containing a carbonate moiety (dialkyl carbonates) is growing and continuing to find many new commercial and synthetic applications in fuel additive, lubricant, polymer, cosmetic, and plasticizer formulations. The longer chain and branched carbonates are typically derived from alcohols that are typically obtained from vegetable oil-based oleochemical feedstocks. Although the excellent properties and commercial interest of various dialkyl carbonates has led to a sizeable body of patent literature, to our knowledge, a systematic analytical characterization, especially of long-chain and branched dialkyl carbonates derived from vegetable oil-based oleochemicals, is not currently available. We have successfully synthesized and characterized dialkyl carbonates, possessing potentially interesting properties, derived from vegetable oil-based alcohols. This research supplies fundamental information about these compounds not readily available to researchers and formulators in the fats and oils industry. The basic knowledge gained from this research has clear importance in the understanding and utilization of the carbonate materials prepared. Finding new methods to use oleochemicals derived from vegetable oils, a renewable resource, and obtain bio-based industrial products not only benefits farmers in the United States, but also helps to decrease our dependence on the ever tightening supply of non-renewable petroleum-based resources.
Technical Abstract: A series of organic carbonates derived from mid-, long-chain and Guerbet alcohols were synthesized in good yields (69.4-79.8%) through a carbonate interchange reaction by heating various linear or Guerbet alcohols with diethyl carbonate in the presence of catalyst, n-dibutyltin oxide. The carbonates were isolated by Kugelrohr distillation or recrystallization from acetone and characterized using Fourier transform infrared spectroscopy (FTIR), gas chromatography (GC), 1H and 13C nuclear magnetic resonance spectroscopy (NMR), and gas chromatography-mass spectrometry (GC/MS). Electron impact (EI) and positive chemical ionization (CI) mass-spectral techniques were utilized to characterize the carbonates. Such materials are currently of commercial interest as lubricants and additives in various industrial applications.