Heat pump the brand name Freon, a trademark of DuPont. Its manufacture is now banned or severely restricted by the Montreal Protocol of August 1987 because of the damage that CFCs cause to the ozone layer if released into the atmosphere. One widely adopted replacement refrigerant is the hydrofluorocarbon (HFC) known as R-134a (1,1,1,2-tetrafluoroethane). Heat pumps using R-134a replaced R-12 (dichlorodifluoromethane) and have similar thermodynamic properties but with insignificant ozone depletion potential and a somewhat lower global warming potential. Other substances such as liquid R-717 ammonia are widely used in large-scale systems, or occasionally the less corrosive but more flammable propane or
United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances stereoisomers in EU Category 1. See also the article: drug precursors The salts of the substances listed in this Table whenever the existence of such salts is possible. The salts of the substances listed in this Table whenever the existence of such salts is possible. The salts of hydrochloric acid and sulphuric acid are specifically excluded from Table II. United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances The United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances of 1988 is one of three major drug control treaties currently in force. It provides additional