C07D 251/56
Preparation of melamine
C07D251/56 (Preparation of melamine) appears on 117 US grants and 104 published applications in this corpus.
Search patents in C07D- Granted patents
- 117
- Published applications
- 104
- Assignees
- 45
- Inventors
- 229
- Latest grant
- 19 Aug 2025
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1978 | 1 | 0 |
| 1979 | 2 | 0 |
| 1980 | 0 | 0 |
| 1981 | 2 | 0 |
| 1982 | 2 | 0 |
| 1983 | 2 | 0 |
| 1984 | 3 | 0 |
| 1985 | 1 | 0 |
| 1986 | 3 | 0 |
| 1987 | 1 | 0 |
| 1988 | 1 | 0 |
| 1989 | 0 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 0 | 0 |
| 1993 | 0 | 0 |
| 1994 | 1 | 0 |
| 1995 | 1 | 0 |
| 1996 | 2 | 0 |
| 1997 | 0 | 0 |
| 1998 | 3 | 0 |
| 1999 | 1 | 0 |
| 2000 | 1 | 0 |
| 2001 | 9 | 1 |
| 2002 | 3 | 4 |
| 2003 | 4 | 8 |
| 2004 | 6 | 8 |
| 2005 | 4 | 3 |
| 2006 | 5 | 4 |
| 2007 | 4 | 9 |
| 2008 | 6 | 4 |
| 2009 | 4 | 5 |
| 2010 | 2 | 4 |
| 2011 | 3 | 4 |
| 2012 | 1 | 6 |
| 2013 | 3 | 4 |
| 2014 | 1 | 0 |
| 2015 | 8 | 0 |
| 2016 | 1 | 2 |
| 2017 | 4 | 4 |
| 2018 | 4 | 3 |
| 2019 | 2 | 3 |
| 2020 | 2 | 3 |
| 2021 | 3 | 3 |
| 2022 | 0 | 1 |
| 2023 | 4 | 2 |
| 2024 | 3 | 9 |
| 2025 | 4 | 4 |
| 2026 | 0 | 6 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- Melamine process with a two-stage purification of melamine offgas19 Aug 2025US 12,391,655 B1Casale SA
- Production of urea and melamine24 Jun 2025US 12,338,201 B2Stamicarbon B. V.
- Coupled urea melamine plant3 Jun 2025US 12,319,662 B2Stamicarbon B. V.
- Multiproduct low biuret urea production4 Mar 2025US 12,240,800 B2Stamicarbon B. V.
- Urea and melamine production12 Nov 2024US 12,139,448 B2Stamicarbon B. V.
- Process for the synthesis of melamine with an optimized dissolution and ammonolysis step8 Oct 2026US 2026/0308133 A1Eurotecnica Contractors & Engineers S.p.A.
- Process for the production of high-purity melamine from the pyrolysis of urea, with optimization of the deammoniation step of the mother liquors8 Oct 2026US 2026/0308134 A1Eurotecnica Contractors & Engineers S.p.A.
- Melamine process with urea melt-based washing of melamine offgas1 Oct 2026US 2026/0297039 A1Casale SA
- A process and plant for the synthesis of urea and melamine30 Apr 2026US 2026/0116850 A1Casale SA
- Melamine process with purification of melamine offgas5 Mar 2026US 2026/0062392 A1Casale SA
Most cited
By later US patents
- Production of chemical compounds29US 9,084,978 B22015
- Process for purifying urea-containing waste water and process for preparing melamine26US 4,308,385 AStamicarbon B. V. · 1981
- Anhydrous high-pressure melamine synthesis26US 4,565,867 AMelamine Chemicals, Inc. · 1986
- Process for the production of highly pure melamine20US 5,721,363 AAgrolinz Melamin GmbH · 1998
- Melamine of improved purity produced by high-pressure, non-catalytic process17US 5,514,796 AMelamine Chemicals, Inc. · 1996