Method for Preparation of Mononitrated Aromatic Compounds

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

This patent describes an improved method for producing mononitrated aromatic compounds (important intermediates for dyes, pharmaceuticals, and explosives) by nitrating aromatic compounds with nitric acid in a two-phase liquid system. One phase is an ionic liquid and the other is aqueous nitric acid, which is continuously or repeatedly exchanged during the reaction to keep the acid concentration high and maintain efficient conversion. The process features easy separation of products, reusability of the ionic liquid, regeneration of the nitric acid phase using NO2 and air, and can be run continuously for industrial scale production.

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

• Manufacturing of mononitrated aromatic compounds such as nitrotoluene or nitrobenzene for use in dyes, pharmaceuticals, and agrochemicals.
• Production of aromatic amines via further chemical transformations, such as reduction of mononitroaromatics.
• Industrial production of intermediates for explosives, polymers, and specialty chemicals.
• Eco-friendly and efficient alternative to traditional nitration processes in chemical plants, particularly for companies seeking to reduce hazardous waste.
• Continuous-flow systems for large-scale or automated chemical manufacturing.

BenefitsContent extracted from patent full text and abstract with AI.

• High selectivity for mononitration with minimal byproduct (dinitration) formation, ensuring product purity and safety.
• The continuous/exchange of nitric acid phase keeps nitration rates high and ensures complete conversion of starting materials.
• Process avoids the need for sulfuric acid, reducing sulfate-containing waste and improving ecological impact.
• Ionic liquids used are stable under conditions (not prone to nitration), allowing easy recycling, lowering process costs, and reducing resource consumption.
• Distinct phase separation simplifies downstream purification, product recovery, and recycling of ionic liquids and nitric acid.
• Flexible operation in either batch or continuous modes makes the method suitable for both small- and large-scale deployments.
• Waste streams are minimal and predominantly water, with options to regenerate and recycle valuable reagents, supporting sustainability and cost reduction.

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Inventors & Applicants

Patent Abstract

The invention discloses a method for preparation of mononitrated aromatic compounds in a liquid-liquid biphasic solvent system with aqueous nitric acid as one phase and ionic liquids (ILs) as the second phase, wherein the nitric acid is continuously exchanged during the reaction.