Liquid hydrocarbon based fuels, such as gasoline and diesel fuel, are known to display a certain degree of toxicity when contacted with biological systems. For example, the toxicological effects of fuels on mice were reported by C. S. Baxter and M. L. Miller in an article titled “Mechanism of Mouse Tumor Promotion by N-Dodecane”, Carcinogenesis, Vol. 8, pages 1787-1790 (1987) and by Walborg et al. in an article titled “Short-term Biomarkers of Tumor Promotion in Mouse Skin Treated with Petroleum Middle Distillates”, Toxicological Sciences, Vol. 45, pages 137-145 (1998). See also “A 90-Day Toxicity Study of the Effects of Petroleum Middle Distillates on the Skin of C3H Mice” by James J. Freeman et al. in Toxicology and Industrial Health Vol. 6; 3/4, pages 475-491 (1990) and “The Role of Dermal Irritation in the Skin Tumor Promoting Activity of Petroleum Middle Distillates” by Craig S. Nessel et al., Toxicological Sciences, Vol.49, pages 48-55 (1999). Walborg et. al. used as a biomarker chemically induced epidermal hyperplasia in mice. In their tests, the increase in epidermal thickness observed after repeated treatments of mice over a two week period was evaluated. This test is a relatively rapid and cost-effective method for determining the biological activity of transportation fuels when applied topically.
Transportation fuels having lowered biological activity are highly desirable; however, few practical methods for manufacturing transportation fuels which display reduced toxicity have been reported. Studies have suggested that mineral oil when mixed with petroleum-derived middle distillates is able to reduce the skin irritation in mice. See J. J. Freeman et al. “Evaluation of the Contribution of Chronic Skin Irritation and Selected Compositional Parameters to the Tumorigenicity of Petroleum Middle Distillates in Mouse Skin” Toxicology, Vol. 81, pages 103-112 (1993) and Craig S. Nessel et al. “A Comprehensive Evaluation of the Mechanism of Skin Tumorigenesis by Straight-Run and Cracked Petroleum Middle Distillates” Toxicological Sciences, Vol. 44, pages 22-31 (1998).
The present invention is directed to a transportation fuel, suitable for use in a diesel engine which, using the methods described in Walborg et al., will display a reduced level of toxicity as evidenced by the difference between the epidermal thickness in mice treated with the fuel composition as compared to controls. The invention is also directed to a process for preparing the lowered toxicity transportation fuels of the invention.
For the purpose of this disclosure the term “transportation fuels” refers to a liquid transportation fuel. Generally, liquid transportation fuels will refer to fuels boiling within the range of gasoline, jet, or diesel. However, as will be explained in greater detail further on in this disclosure, the unique fuel compositions of this invention may have a boiling range outside of the boiling ranges of conventional transportation fuels. Fuel compositions of the present invention are particularly suitable for use as fuel in diesel engines.
As used in this disclosure the word “comprises” or “comprising” is intended as an open-ended transition meaning the inclusion of the named elements, but not necessarily excluding other unnamed elements. The phrase “consists essentially of” or “consisting essentially of” is intended to mean the exclusion of other elements of any essential significance to the composition. The phrase “consisting of” or “consists of” are intended as a transition meaning the exclusion of all but the recited elements with the exception of only minor traces of impurities.