Process for the Synthesis of Aryldiazonium Salts Using Nitrogen Oxides in Oxygen-Containing Gas Streams, Especially from Industrial Waste Gases

Simple SummaryContent extracted from patent full text and abstract with AI.

This patent presents an industrial process for synthesizing aryldiazonium salts by reacting aromatic amines with nitrogen oxides (NO and NO2) present in oxygen-containing gas streams, particularly those found in industrial waste gases. Instead of simply removing harmful NOx emissions from waste gases through conventional methods, this process captures these gases and uses them to produce valuable chemical intermediates (aryldiazonium salts), which can be further used in the production of dyes and other chemicals, hence combining environmental cleanup with useful synthesis.

Use CasesContent extracted from patent full text and abstract with AI.

• Treatment of industrial waste or flue gases to remove NOx emissions while converting them into useful chemical intermediates.
• Production of aryldiazonium salts for dye manufacture, including azo dyes that are widely used in textiles.
• Synthesis of specialty chemicals (e.g., halobenzenes, aromatic nitriles) through Sandmeyer or other classic reactions using the produced diazonium salts.
• Preparation of biaryl compounds for pharmaceuticals, agrochemicals, and electronic materials via cross-coupling or radical reactions.
• Functionalization and coating of surfaces, including use in nanotechnology applications, through diazonium salt intermediates.
• Conversion of waste gases in industries such as metal processing, nitric acid production, and power plants into value-added products instead of pollutants.

BenefitsContent extracted from patent full text and abstract with AI.

• Simultaneous removal (denitrification) of harmful nitrogen oxides from waste gas streams and synthesis of commercially valuable chemical intermediates, improving overall process efficiency.
• Reduces environmental impact and helps meet regulatory targets for NOx emissions in industry.
• Provides an alternative route to aryldiazonium salts that reduces reliance on traditional nitrite sources and hazardous concentrated nitrogen dioxide.
• Can be integrated into existing gas treatment infrastructure (e.g., wet scrubbers) without major modifications, aiding practical adoption.
• Enables the direct use of low-concentration and variable-composition waste gas streams, which are common in real industrial environments, making the method robust and scalable.
• Facilitates further conversions (e.g., production of azo dyes, biaryl compounds) directly from scrubber solutions, streamlining manufacturing processes and reducing waste.

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Patent Abstract

The present invention relates to a process for the synthesis of aryldiazonium salts using nitrogen oxides in oxygen-containing gas streams, especially from industrial waste gases.