Ralf Pfirmann
39Patents
6h-index
23Co-inventors
65Inventor score
Filing activity: Apr 23, 1992 → Apr 30, 2002
Most-cited inventions
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US6001831A | Process for producing quinazoline derivatives | Chemistry; Metallurgy | 53 | Expired |
| US6103659A | Catalyst comprising an amidophosphonium salt for halex reactions | Performing Operations; Transporting | 25 | Expired |
| US6465643B1 | Aminophosphonium compounds | Performing Operations; Transporting | 9 | Expired |
| US5849959A | Derivatives of 2, 3, 6-trifluorophenols and a process for their preparation | Chemistry; Metallurgy | 7 | Expired |
| US5516932A | Halogenated cinnamic acids and esters thereof, processes for the preparation thereof and halogenated aryldiazonium salts | Chemistry; Metallurgy | 7 | Expired |
| US6645904B2 | Aminophosphonium compounds | Performing Operations; Transporting | 7 | Expired |
| US5565612A | Substituted 2-chloro-3,4,5-trifluorobenzenes and a process for their preparation | Chemistry; Metallurgy | 5 | Expired |
| US5410082A | Process for preparing amines | Chemistry; Metallurgy | 4 | Expired |
| US5481032A | Process for the preparation of halogenated benzoic acids | Emerging Cross-Sectional Technologies | 4 | Expired |
| US6075152A | Process for preparing isochroman-3-ones | Chemistry; Metallurgy | 3 | Expired |
| US5478963A | 2,3-difluoro-6-nitrobenzonitrile and 2-chloro-5,6-difluorobenzonitrile-(2,3-difluoro-6-chlorobenzonitrile), process for their preparation and their use for the preparation of 2,3,6-trifluorobenzoic acid | Chemistry; Metallurgy | 3 | Expired |
| US5384413A | Process for the preparation of tetrafluorophthalic acid and/or tetrafluorophthalic anhydride | Chemistry; Metallurgy | 3 | Expired |
| US5965775A | Process for the preparation of 3,5-difluoroaniline | Chemistry; Metallurgy | 2 | Expired |
| US5525258A | Trifluorophenylene compounds, process for their preparation, and their use in liquid-crystalline mixtures | Chemistry; Metallurgy | 2 | Expired |
| US5468863A | Process for the preparation of substituted 2,3-difluoropyridines | Chemistry; Metallurgy | 2 | Expired |
| US5179230A | Process for the preparation of 2,3,4,5-tetrafluorobenzoic acid | Chemistry; Metallurgy | 2 | Expired |
| US5227535A | Process for the preparation of 2-nitro-5-fluoro- or -5-chlorophenol | Chemistry; Metallurgy | 2 | Expired |
| US6187952A | Two-step production of 3-chloro-4-fluoro-benzoyl chloride by chlorination | Chemistry; Metallurgy | 2 | Expired |
| US5274115A | N'-substituted N-amino-3,4,5,6-tetrafluorophthalimides | Chemistry; Metallurgy | 2 | Expired |
| US5874608A | Process for the preparation of esters of aromatic carboxylic acid | Chemistry; Metallurgy | 2 | Expired |
| US5466859A | Process for preparing fluorobenzonitriles | Performing Operations; Transporting | 2 | Expired |
| US5430173A | Process for preparing alkyl 3-hydroxy-2, 4, 5-trifluorobenzoates and/or alkyl 3-alkoxy-2, 4, 5-trifluorobenzoates | Chemistry; Metallurgy | 2 | Expired |
| US5200556A | Process for the preparation of 3,4,6-trifluorophthalic acid and the anhydride thereof | Chemistry; Metallurgy | 1 | Expired |
| US5723658A | Process for the preparation of salts of substituted or unsubstituted phthalic acids | Chemistry; Metallurgy | 1 | Expired |
| US5292967A | Process for producing 2,3-difluoro-6-nitrophenol | Chemistry; Metallurgy | 1 | Expired |
Source: USPTO / EPO open patent data. Inventor disambiguation is heuristic; counts are objective bibliographic measures.