ABSTRACT
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 Properties of the Benzotrifluorides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 Solvent Toxicity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 Worker Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 Cleaning Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 Size and Shape of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 Materials of Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 Volume of Parts to Be Cleaned and Amount of Soil They Contain. . . . . . . . . . . . . 161 Soil Loading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 Cold Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 Mechanical Agitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 Heated Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 Solvent Blends. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Compatibility with Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Compatibility with Polymers and Elastomers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Approved Military and Aerospace Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Reclamation and Disposal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
[Editor’s note: Many factors impact the cleaning options available to components manufacturers. The situation with the benzotrifluorides illustrates the impact of overall business plans of chemical producers. Recently, as this book was going to press, Occidental Chemical, the U.S. producer of benzotrifluorides, announced its intention to exit the market, ceasing production of parachlorobenzotrifluoride (PCBTF) and offering the business for sale. At this point, the future of PCBTF and related compounds as cleaning agents is not known, although some imported PCBTF may be available.]
Despite the uncertainty, this chapter has been included for two reasons. For one thing, PCBTF has been found to be a valid option for some components manufacturers. In addition, Mr. Skelly has written a thoughtful approach to cleaning options. PCBTF has been introduced as a substitute for mineral spirits, and it is particularly valuable in areas of poor air quality. In Southern California, some local regulations explicitly depend on PCBTF for cold cleaning. In addition, because it is neither a VOC or a HAP, PCBTF has been used along with acetone in the reformulation of coatings to meet regulatory constraints. This is perhaps an object lesson to all of us, including end users, formulators, equipment manufacturers, and regulators that depending on a single or primary chemical to resolve major problems may not be prudent. PCBTF is produced throughout the world, but it is primarily a chemical intermediate, not a cleaning agent. In the interest of assuring options, it is hoped that the material will continue to be made available with the appropriate technical support and product stewardship.—B.K.]
OVERVIEW
Three commercially available benzotrifluorides, benzotrifluoride (BTF), parachlorobenzotrifluoride (PCBTF) and 3,4-dichlorobenzotrifluoride (DCBTF), have potential as replacements for ozone-depleting compounds and other organic solvents. Because it is exempt as a volatile organic compound (VOC), PCBTF is used in cleaning applications, particularly in areas with high regulatory constraints.
