Separating Long Chain Amino and Dibasic Acids via pH Control
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Solution Overview
Problem
Current processes for producing long chain nylons are inefficient due to high energy requirements and contamination from impurities, leading to difficulties in separating and recovering long chain amino acids, dibasic acids, short chain alkyl amines, and short chain alkanoic acids, resulting in economic and environmental challenges.
Innovation Solution
A process involving alkali hydroxide or acid hydrolysis of mixed amide derivatives to separate and recover these components, utilizing distillation, extraction, and acidification to achieve high yields and purity, with the use of organic solvents and pH adjustments to enhance solubility and phase separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If step-wise neutralization in highly dilute concentration is used to isolate amino acids and dibasic acids, then product purity is improved, but energy consumption increases substantially
Solution Approach 1:
The patent changes the concentration parameter from highly dilute to concentrated conditions, and alters the separation mechanism from step-wise neutralization to pH-controlled selective precipitation. This allows isolation of amino acids and dibasic acids in concentrated form directly from hydrolysis, eliminating energy-intensive concentration steps while maintaining high purity through controlled pH precipitation
Solution Approach 2:
The patent utilizes pH-controlled phase transitions where amino acids and dibasic acids are selectively precipitated from the concentrated hydrolysis mixture by adjusting pH to specific ranges. This phase separation method enables direct isolation of pure products from concentrated solution without requiring dilution and subsequent energy-intensive concentration operations
2Quantity of substance
If commercial starting materials containing various fatty acids are used, then production cost is reduced, but product purity deteriorates due to impurity contamination
Solution Approach 1:
The patent applies local quality control by targeting specific pH ranges for precipitation of different product types. Amino acids precipitate at pH 2-4, while dibasic acids precipitate at pH 4-6, allowing selective isolation of each product type even in the presence of various fatty acid impurities. This localized pH control ensures high purity products from crude starting materials
Solution Approach 2:
The patent extracts and removes impurity fatty acids through selective pH precipitation. By controlling pH to precipitate amino acids and dibasic acids at specific stages, impurity fatty acids remain in solution or are removed in different fractions, effectively separating desired products from contaminants without requiring additional purification steps
3Productivity
If hydrolysis of mixed amide derivatives is performed, then long chain amino acids and dibasic acids are produced, but short chain alkyl amines and alkanoic acids are generated as unwanted byproducts
Solution Approach 1:
The patent converts the harmful byproducts into beneficial products by implementing separate recovery streams. Short chain alkyl amines are recovered by basifying the aqueous phase to pH 10-12 and extracting with organic solvent, while short chain alkanoic acids are recovered by acidifying to pH 2-4 and extracting. This transforms waste disposal costs into product recovery opportunities, improving overall process economics
4Object-affected harmful factors
If aqueous waste mother liquor is discharged, then environmental pollution occurs, but recovery processes increase operational complexity
Solution Approach 1:
The patent recovers valuable components from aqueous waste mother liquor by adjusting pH to precipitate remaining amino acids and dibasic acids. The recovered solids are filtered and dried to produce additional product, while the depleted aqueous solution can be evaporated to recover inorganic salts. This complete recovery approach eliminates wastewater discharge while adding value from previously wasted streams
Solution Approach 2:
The patent implements multi-functional pH adjustment steps that simultaneously achieve multiple objectives: isolating amino acids, isolating dibasic acids, recovering byproducts, and treating waste streams. A single pH adjustment operation performs separation, purification, and waste treatment functions, reducing overall process complexity despite comprehensive resource recovery
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
The process effectively separates and recovers long chain amino acids and dibasic acids with high purity, reducing waste and energy consumption, and allows for the recovery of other fatty acids, thereby improving the economic viability and environmental sustainability of nylon production.
Implementation Method 1
A process involving alkali hydroxide or acid hydrolysis of mixed amide derivatives to separate and recover these components
Implementation Method 2
utilizing distillation, extraction, and acidification to achieve high yields and purity
Implementation Method 3
utilizing distillation, extraction, and acidification to achieve high yields and purity, with the use of organic solvents and pH adjustments
Implementation Method 4
utilizing distillation, extraction, and acidification to achieve high yields and purity, with the use of organic solvents and pH adjustments to enhance solubility and phase separation
Data Source
AI summary
There is disclosed a process for the separation of long chain amino acid and long chain dibasic acid, comprising: (1) recovering alkylamine from an aqueous solution of an alkali hydroxide hydrolysis of the mixed amide derivatives by distilling or by extracting with an extractant solvent; (2) cooling the aqueous solution of step (1) to precipitate a mixed alkali salts of long chain amino acid and dibasic acid; (3) recovering the mixed alkali salts of long chain amino acid and dibasic acid to provide a mother liquor; (4) separating long chain amino acid and dibasic acid by acidification-extraction of long chain dibasic acid with an extractant solvent or by selective dissolution of alkali salt of long chain amino acid in an aqueous solvent; and (4) adding an acid to the mother liquor of step (3) to obtain alkanoic acid.