Chinese name: β-alanine CAS No.: 107-95-9
English name: β-alanine
Alias: beta-aminopropionic acid; 3-aminopropionic acid; β-aminopropionic acid; β-alanine; β-primary oil amino acid; β-serine; alanine
Molecular formula: C3H7NO2
Appearance and traits: colorless powder
Melting point: 200oC
Water soluble: soluble in water, slightly soluble in ethanol, insoluble in ether and acetone
An amino acid is a compound in which a hydrogen atom on a carbon atom of a carboxylic acid is substituted with an amino group. The amino acid molecule contains two functional groups, an amino group and a carboxyl group. Similar to the hydroxy acid, the amino acid can be classified into α-, β-, γ-...w-amino acids according to different positions of the amino group attached to the carbon chain. However, the amino acids obtained after proteolysis are all α-amino acids, and there are only twenty kinds, which are the basic units that constitute proteins.
Amino acids can exert the following effects through metabolism in the human body: 1 synthesizing tissue proteins; 2 converting into ammonia-containing substances such as acids, hormones, antibodies, creatine; 3 converting into carbohydrates and fats; 4 oxidizing into carbon dioxide and water and urea, generate energy.
Essential amino acids refer to amino acids that the body itself cannot synthesize or synthesize at a rate that does not meet the needs of the human body and must be taken from food. It is essential for the human body (or other vertebrates), but not synthetic in the body. It must be supplemented with amino acids from food, called essential amino acids. There are eight essential amino acids for adults: lysine, tryptophan, phenylalanine, methionine, threonine, isoleucine, leucine, and valine.
Non-essential amino acids refer to those that can be synthesized in animals. Non-essential amino acids do not require externally supplemented amino acids as a source of nutrients. Generally, the essential amino acids in plants and microorganisms are synthesized by themselves, and these are called non-essential amino acids. Non-essential amino acids for humans are glycine, alanine, valine, tyrosine, serine, cysteine, asparagine, glutamine, aspartic acid, glutamic acid. These amino acids are synthesized from a metabolite of a carbohydrate or from an essential amino acid, and are further introduced into an amino group to form an amino acid by a transamination reaction. It is known that even the ingestion of non-essential amino acids is advantageous for growth.
The simplest β-amino acid has the effect of increasing the content of imidazole dipeptide in muscle, increasing antioxidant capacity, enhancing muscle buffering capacity and anti-fatigue. It is also a component that constitutes pantothenic acid, coenzyme A, etc., and combines with histidine to form carnosine and its derivative goose carnosine (present in animal muscle). It is a non-essential amino acid that does not participate in protein synthesis. It has been widely used as a nutritional supplement for strengthening muscle endurance. Studies have shown that β-alanine can improve animal performance, regulate muscle growth and myogenic peptide content. In the medical field, it is widely used in the fields of feed, food, etc., in addition to the synthesis of pamidronate and balsalazide.
A peptide is a compound in which two or more amino acids are linked by peptide bonds. It plays an important physiological role in the human body and exerts physiological functions. An active polypeptide is referred to as an active peptide, also known as a biologically active peptide or a biologically active polypeptide. Active peptides are the most important active substances in the human body. It is precisely because of its increase or decrease in the amount of secretion in the body that humans have a cycle of childhood, childhood, adulthood, and old age until death. Injecting active peptides breaks the cycle of life, thereby achieving the miraculous effect of prolonging life and effectively slowing down aging.
1. Acrylic method (industrialization)
Under higher temperature and pressure conditions, the acrylic acid, acrylate or acrylate is aminated with ammonia to obtain the β-aminopropionic acid product. The amination process of acrylic acid is as follows:CH2 =CH -COOH +NH3→H2N-CH2 -CH2 –COOH
The acrylic route is simple in process, high in yield, and high in product purity, but it is necessary to break the chemical balance.
2. Acrylonitrile method (industrialization)
There are two types of methods for synthesizing beta aminopropionic acid using acrylonitrile as a substrate, namely direct amination and ammoniation hydrolysis. At present, most domestic manufacturers use acrylonitrile amination hydrolysis. Due to the presence of this side reaction, the reaction yield is generally not high. Moreover, due to the formation of a large amount of inorganic salts in the hydrolysis process, product purification is difficult and the purity of the product is not high.
The direct amination process is a one-step reaction of acrylonitrile and ammonia water by direct amination at high temperature and pressure to synthesize β-aminopropionic acid:
CH2 =CH -CH2 -CN +NH3→H2N -CH2 -CH2 –COOH
The reaction is carried out in two steps. First, acrylonitrile is aminated with ammonia to form β-aminopropionitrile. The β-aminopropionitrile is then hydrolyzed under acidic or basic conditions to be β-aminopropionic acid.
CH2 =CH -CN→H2N -CH2-CH2-CN → H2N -CH2 -CH2 –CO
3. β-Aminopropionitrile method: β-Aminopropionitrile is used as a substrate. The cyano group synthesizes β-aminopropionic acid by hydrolysis in one step. There are acid hydrolysis methods, alkali hydrolysis methods, and enzyme-catalyzed hydrolysis methods depending on the catalyst.
H2N -CH2 -CH2 -CN→ H2N-CH2 -CH2 -COOH +NH3
In actual production, liquid alkali (sodium hydroxide or potassium hydroxide) is mostly used to hydrolyze β-aminopropionitrile, and then acid neutralized. This method is characterized by high reaction yield, and the disadvantage is that a large amount of salt is produced. Some domestic manufacturers produce aminopropionic acid by this method.
4. β-Aminopropanol method: converts β-aminopropanol to β-aminopropionic acid under the action of an oxidizing agent.
NH2 -CH2 -CH2 -CH2 -OH→NH2 -CH2 -CH2 -COOH
5. Succinimide method: Degradation reaction of succinimide in alkaline sodium chlorate solution (sodium hypochlorite, sodium hydroxide and sodium carbonate). The product is complicated to be purified, and the yield is not about 50% (calculated as succinimide), so it is not industrialized:
The steps are as follows:
a) preparing a substrate: a concentration of 5g / L -80g / L of L-aspartic acid substrate solution into the enzyme reactor, with an alkalinizing agent to adjust the pH of 5.0-8.5;
b) Enzymatic reaction: The enzyme-containing bacterial solution is added to the substrate solution for catalytic reaction. An appropriate amount of L-aspartic acid was added in portions during the reaction to adjust the pH of the reactants to 5.0-9.0. The enzyme-containing bacterial liquid is obtained by fermenting, concentrating and crushing the engineering bacteria with high yield of L-aspartate α-decarboxylase;
c) The reactants in the enzyme reactor are filtered, decolorized, and crystallized to obtain β-alanine. L-aspartic acid is converted to β-alanine using an enzyme-containing bacterial solution.
The process has the following advantages: mild production conditions, simple process, low environmental pollution; simple downstream extraction, high product quality, purity up to 99.0%; and conversion efficiency of β-alanine up to 99.5%.
Summary: Domestic industrial production mainly uses acrylonitrile ammonia hydrolysis. Most of these methods require strong alkali, strong acid, high temperature, high pressure and other conditions, and the product purification is cumbersome and has environmental pollution problems.
Some domestic plants began to use the fermentation method gradually. The survey found that some factories used to do alanine, but due to environmental problems, many small factories in Hubei and Hebei have stopped production in recent years.