2-Nitroethanol Purification via Solvent Extraction and Vacuum Concentration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for preparing 2-nitroethanol are plagued by high risks of explosion, low yields, excessive reagent consumption, environmental pollution, and high costs, making them unsuitable for industrial production.
Innovation Solution
A method involving the reaction of paraformaldehyde with nitromethane under base catalysis, followed by extraction with C3–C9 aliphatic esters to separate and purify 2-nitroethanol, using specific solvents like propyl butyrate or butyl butyrate, under controlled temperature and vacuum conditions to achieve high yield and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature azeotropic distillation is used to collect 2-nitroethanol, then the product can be obtained, but the method has great risk of explosion and poor yield
Solution Approach 1:
The patent employs extraction followed by vacuum concentration to obtain 2-nitroethanol, avoiding high-temperature azeotropic distillation. The extraction process utilizes solvent selection to separate 2-nitroethanol from the reaction mixture at lower temperatures, and vacuum concentration removes the extraction solvent at reduced temperature and pressure, thereby eliminating the explosion risk associated with high-temperature distillation while maintaining high product yield
Solution Approach 2:
The patent changes the operating parameters from high-temperature distillation to low-temperature extraction and vacuum concentration. By operating at temperatures below 60°C during vacuum concentration and using appropriate extraction solvents, the method achieves both safety improvement and high yield (80-85%)
2Manufacturing precision
If extremely excessive consumption of nitromethane is used to improve reaction selectivity, then selectivity improves, but the method is not suitable for industrial production
Solution Approach 1:
The patent optimizes the reaction parameters including the molar ratio of nitromethane to paraformaldehyde, base catalyst concentration, and reaction temperature to achieve high selectivity without excessive reagent consumption. The extraction process further enhances selectivity by separating 2-nitroethanol from side products based on solubility differences
Solution Approach 2:
The patent uses extraction with specifically selected solvents to separate 2-nitroethanol from the reaction mixture, effectively removing the desired product from equilibrium and driving the reaction forward with moderate reagent ratios, thereby achieving high selectivity without requiring extremely excessive nitromethane consumption
3Productivity
If excess sodium nitrite and heavy metal salts are used to prepare 2-nitroethanol, then the reaction proceeds, but environmental pollution is caused
Solution Approach 1:
The patent replaces heavy metal salt catalysts with base catalysts such as potassium hydroxide or sodium hydroxide, which are less environmentally harmful. The extraction solvents used are also selected to be environmentally friendly and easily removable, eliminating the persistent pollution problems associated with heavy metal salts
Solution Approach 2:
The patent changes the catalyst system from heavy metal salts to base catalysts and adjusts reaction conditions to achieve comparable or better reaction efficiency without environmental pollution. The extraction and vacuum concentration steps further ensure no harmful residues remain in the final product
4Productivity
If expensive reagents are used to prepare 2-nitroethanol, then the reaction proceeds efficiently, but the method is not suitable for large-scale production
Solution Approach 1:
The patent employs inexpensive base catalysts such as potassium hydroxide or sodium hydroxide instead of expensive reagents like silver nitrite. The extraction solvents selected are also cost-effective and readily available, making the overall process economically viable for large-scale production while maintaining high reaction efficiency and product yield
Solution Approach 2:
The patent uses extraction solvents that can be easily removed by vacuum concentration and potentially recovered and reused. The base catalysts used are inexpensive and do not require complex recovery processes, significantly reducing production costs compared to methods using expensive reagents that need to be discarded or complexly recovered
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method achieves a high yield of 80%-85% pure 2-nitroethanol with reduced risks, using readily available and inexpensive solvents, ensuring excellent safety and industrial applicability.
Implementation Method 1
selecting an extraction solvent in which the 2-nitroethanol (I), 2-nitro-1,3-propanediol (II) and tris(hydroxymethyl) nitromethane (III) are different in solubility; adding the extraction solvent to the mixture followed by extraction, separation
Implementation Method 2
the vacuum concentration is performed under a vacuum degree of 0.1 ̃10 mmHg at 0 ̃60° C.
Data Source
AI summary
A separation and purification method of 2-nitroethanol, including: (a) reacting paraformaldehyde with nitromethane in the presence of a base to obtain a mixture of 2-nitroethanol (I), 2-nitro-1,3-propanediol (II) and tris(hydroxymethyl) nitromethane (III); and (b) selecting an extraction solvent in which 2-nitroethanol (I), 2-nitro-1,3-propanediol (II) and tris(hydroxymethyl) nitromethane (III) are different in solubility; adding the extraction solvent to the mixture followed by extraction, separation, and vacuum concentration to obtain the 2-nitroethanol (I).