Trichlorethylene, toxicity

Toluene is less toxic than benzene, but more dangerous than xylene with respect to its toxicity Trichlorethylene, often recommended for use in place of CC/4, is about half as toxic as is often used instead of it. Some persons even grow adicted to it (Refs 80b 110, p 84) Trinitrotoluene. Pb and Fe produce explosive substances with TNT in the presence of HN03. These can be ignited by heat, shock, friction, or contact with concentrated nitric and sulfuric acids (Ref 85a)... 

Increase of the narcotic power and the toxicity in comparison with the corresponding saturated compound. Ethylene, acetylene, trichlorethylene, divinyl oxide and, by extension, cyclopropane are examples of unsaturated narcotics. 

Many solvents have been suggested for use in these decaffeination processes. Initially benzene was used but it is never used today because of its toxicity and flammability. When chlorinated solvents first became available at low prices, trichlorethylene was sometimes used but this solvent also has now been superseded. Methylene chloride is the only chlorinated hydrocarbon currently used as a decaffeination solvent. Other commercially used solvents are ethyl acetate, coffee oil and other triglycerides [12]. In addition to the decaffeination processes outlined above, which are based on conventional solvent extraction with organic solvents, water decaffeination and supercritical carbon dioxide extraction have now become well-established processes. It is still necessary in these processes to humidify the beans before extraction (step 1) and to return them to their initial humidity afterwards (step 4), but the remaining steps in the extraction process differ substantially from those in the conventional solvent extraction processes. Steam stripping (step 3), for example, is only necessary in processes using organic solvents. 

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