Comproportionation-based autocatalytic cycles and related methods
US-2025382173-A1 · Dec 18, 2025 · US
Nitric acid
Nitric acid · Cooperative Patent Classification (CPC)
Chemical and metallurgical processes, compounds, and materials.
Related technology areas
Mapped technology topics for this CPC code.
| Metric | Value |
|---|---|
| CPC code | C01B21/38 |
| Official title | Nitric acid |
| Display label | Nitric acid |
| Total patents | 63 |
Filing trend
Year-over-year patent counts classified under this CPC code.
Filing activity over the last five years is stable.
| Year | Patents |
|---|---|
| 2015 | 3 |
| 2016 | 3 |
| 2017 | 9 |
| 2018 | 3 |
| 2019 | 5 |
| 2020 | 2 |
| 2021 | 6 |
| 2022 | 4 |
| 2023 | 6 |
| 2024 | 14 |
| 2025 | 5 |
| 2026 | 3 |
Representative patents
Representative publications under this CPC code from precomputed stats, or recent filings when stats are unavailable.
Method for operating a nitric acid plant and nitric acid plant
US-2025368511-A1 · Dec 4, 2025 · US
Protective fluid for alumina, protection method, and production method for semiconductor substrate having alumina layer using same
US-12338381-B2 · Jun 24, 2025 · US
Mono pressure system for producing nitric acid and method of operating thereof
US-2025091869-A1 · Mar 20, 2025 · US
Mono pressure system for producing nitric acid and method of operating thereof
US-2025011171-A1 · Jan 9, 2025 · US
System, vehicle and method for lubricating a hydrogen injector in a vehicle
US-12140114-B1 · Nov 12, 2024 · US
Dual pressure system for producing nitric acid and method of operating thereof
US-2024367976-A1 · Nov 7, 2024 · US
Integrated process for the synthesis of ammonia and nitric acid
US-2024359982-A1 · Oct 31, 2024 · US
System, Vehicle and Method for Lubricating a Hydrogen Injector in a Vehicle
US-2024360809-A1 · Oct 31, 2024 · US
Mono pressure system for producing nitric acid and method of operating thereof
US-2024343576-A1 · Oct 17, 2024 · US
Dual pressure system for producing nitric acid and method of operating thereof
US-2024343577-A1 · Oct 17, 2024 · US
Dual pressure system for producing nitric acid and method of operating thereof
US-2024336481-A1 · Oct 10, 2024 · US
Catalyst system and method for the catalytic combustion of ammonia to form nitrogen oxides in a medium-pressure system
US-12109553-B2 · Oct 8, 2024 · US
Integrated energy systems for energy production and green industrial applications, such as the production of nitric acid
US-2024308850-A1 · Sep 19, 2024 · US
Ammonia mixing system and use thereof
US-2024299889-A1 · Sep 12, 2024 · US
Process for production of nitric acid provided with a secondary abatement treatment
US-2024246819-A1 · Jul 25, 2024 · US
SYSTEM FOR EVACUATING NOx GASES FROM A NITRIC ACID STORAGE TANK
US-2024228284-A1 · Jul 11, 2024 · US
Knitting of precious metal networks and a method using same
US-11959208-B2 · Apr 16, 2024 · US
Ammonia burner for nitric acid production
US-2024002231-A1 · Jan 4, 2024 · US
Mono-pressure plant for the production of nitric acid and method for operating same
US-2023382734-A1 · Nov 30, 2023 · US
Frequently asked questions
Answers are generated from the same data shown on this page.
- What is CPC C01B21/38?
- CPC C01B21/38 is the Cooperative Patent Classification code for “Nitric acid.”
- How many patents are filed under CPC C01B21/38 (Nitric acid)?
- Our database includes 63 publications tagged with this CPC code.
- Is patent activity under CPC C01B21/38 growing?
- Publication counts under this code: 14 in 2024 vs 5 in 2025 (latest complete years).