Historical Perspectives on Vegetable Oil-Based Diesel Fuels

Biodiesel, defined as monoalkyl esters of vegetable oils or animal fats (Scheme 1), is a promising alternative fuel for use in compression-ignition (diesel) engines and is being produced or used commercially in numerous countries around the world, including the United States, Austria, the Czech Republic, France, Germany, Italy, Malaysia, and Sweden. It is generally known that vegetable oils were tested as diesel fuels well before the energy crises of the 1970s and early 1980s generated renewed interest in alternative fuels, but details on the first uses (until the early 1950s) are often unclear or presented inconsistently in the literature. Valuable insights into the use of vegetable oils and their derivatives as diesel fuels were achieved during that time, only to be rediscovered beginning in the late 1970s. This article will discuss the history of biodiesel or, more generally, that of vegetable oil-based diesel fuels and correlate it with current use. Most literature references used here were found through a Chemical Abstracts search or are listed in a publication summarizing literature prior to 1949 on fuels from agricultural sources (1). After the 1940s, literature on vegetable oil-based diesel fuels is very sparse until the late 1970s. Although discussed later in this article in more detail, two references (2,3) describing the first use of a fuel meeting the current definition of biodiesel are worth close examination.