Grünenthal prohibited the research and manufacture of penicillin by German companies. When the ban was lifted, Grünenthal was the first company to introduce penicillin in the postwar period into the German market. This investment achieved a big financial boost for the company. Chemie Grünenthal synthesized thalidomide in 1954 and acquired a 20-year patent. Soon after obtaining a patent in April 1954, the company started clinical trials, and as early as November 1956, marketed the drug for the treatment of respiratory infections under the trade name Grippex, a combination drug that contained thalidomide, quinine, vitamin C, phenacetin, and acetylsalicylic acid. Researchers at
Pyrophosphoric acid red heat of a sodium phosphate salt. It was found that phosphoric acid when heated to red heat formed pyrophosphoric acid that was readily converted to phosphoric acid by hot water. Pyrophosphoric acid Pyrophosphoric acid, also known under the name diphosphoric acid, is colorless, odorless, hygroscopic and is soluble in water, diethyl ether, and ethyl alcohol. The anhydrous acid has two different forms, which melt at 54.3 °C and 71.5 °C. It is best prepared by ion exchange from sodium pyrophosphate or by reacting hydrogen sulfide with lead pyrophosphate. When phosphoric acid is dehydrated pyrophosphoric acid is produced as one