pyridine-4-carboxylic acid

Amino acids are widely used. Looking at "Tiangong Kaiwu", it can be understood.
In the field of food, amino acids are a wonderful seasoning. It can increase the freshness of the taste and make it thick and alcoholic. If you treat people's meals and add amino acids, the taste of the delicious food will be special, fresh and delicious, and everyone will love it. Although there are no refined amino acids in ancient times, there are also natural ones in the ingredients, such as mushrooms, seafood, etc., which have the effect of making the taste fresh, and this is also the work of amino acids.
In the way of medicine, amino acids also have their uses. The human body needs amino acids to form various physiological functions. All kinds of amino acids combine to help the production of proteins, which is related to the growth and repair of the body. And in the field of nerve conduction, amino acids also participate in it, which can maintain the normal operation of the nerves. If there is a deficiency, or cause physical diseases.
In the industrial world, amino acids also show their ability. In the fermentation industry, as a source of nourishment for strains, assisting in the colonization of bacteria, making the work of fermentation go smoothly, to produce all kinds of useful things. And in the manufacture of leather, amino acids can tanned leather, making the leather flexible and durable.
In the field of agriculture, amino acids can be used as additives for fertilizers. It can promote the absorption of nutrients, strengthen its resistance, and make the seedlings strong and fruitful. It can also be used as a feed additive to increase the quality of feed, promote the growth of livestock and poultry, and improve its disease resistance.
All in all, the use of amino acids in food, medicine, industry, and agriculture is important, and it is related to the people's livelihood and cannot be underestimated.

Borax, its physical properties are unique. Borax is a colorless translucent crystal or white crystalline powder, which is soft and delicate to the touch. It often appears crystal clear in sunlight.
Its brittle nature is easy to break, and the crushing surface is smooth and glassy. The density of borax is moderate, about 1.73 g/cm3. Compared with many common ores, it is not heavy, and it feels light in the palm of your hand.
Furthermore, the solubility of borax is also an important physical property. It is easily soluble in water, especially in hot water, and the aqueous solution is weakly alkaline. When borax is dissolved in water, it is lightly smelled, and there is no special smell. The solution is clear and transparent, without the slightest appearance of turbidity.
The melting point of borax is also considerable, about 743 ° C. When it encounters a hot topic, borax will gradually melt into a colorless glass-like substance. After cooling, the glass-like substance will solidify and form, and the shape and texture will undergo wonderful changes, which is of great ornamental and research value.
In addition, the crystal structure of borax is also unique. Its internal atoms are arranged in an orderly manner, forming a regular lattice structure. This structure endows borax with unique physical properties, making it widely used in many fields.

Amino acid is a class of organic compounds containing amino and carboxyl groups. Its chemical properties are quite unique and have amphoteric characteristics.
Cover because of its molecular presence of both basic amino groups and acidic carboxyl groups. In an acidic environment, amino groups can bind protons to make amino acids positively charged; in an alkaline environment, carboxyl groups can dissociate protons and make amino acids negatively charged. This amphoteric property allows amino acids to exist in different ion forms in media with different pH levels, which has a profound impact on their participation in many chemical reactions and physiological processes in organisms. The carboxyl groups of
amino acids can be esterified with alcohols. Under specific conditions, the hydroxyl groups in the carboxyl groups dehydrate and condensate with the hydroxyl groups of alcohols to form esters and water. This reaction is of great significance in the field of organic synthesis and can be used to prepare compounds with specific structures.
And the amino group of the amino acid can participate in the nucleophilic substitution reaction. Because the nitrogen atom in the amino group has a lone pair of electrons and is nucleophilic, it can attack suitable electrophilic reagents, such as halogenated hydrocarbons, etc. The nitrogen atom bonds with the carbon atom in the halogenated hydrocarbons, and the halogen atom leaves to realize the substitution of the amino group, and then constructs novel carbon-nitrogen bonds, which enriches the structural types of organic compounds.
Furthermore, the amino acid molecules can interact with the carboxyl group through the amino group to dehydrate and condensate to form peptide bonds. Many amino acids are connected by peptide bonds, and then form polypeptides and even proteins. This process is the basis of protein synthesis in life, and is crucial for maintaining life activities, building biological structures and exercising physiological functions. Many enzymes, antibodies and other proteins are polymerized from amino acids in specific sequences, and their unique chemical properties determine the high-level structural and functional properties of proteins.

There are many methods for synthesizing 4-carboxylic acids, which are described in ancient methods.
First, the method of esterification and hydrolysis can be used. Take the corresponding alcohol and acid anhydride, catalyze with an appropriate catalyst, and esterify them. If you choose alcohols, use sulfuric acid as a catalyst, and place them in a reactor with acid anhydride, control them at a suitable temperature and pressure to promote their esterification reaction. After the reaction is completed, hydrolysis with alkali solution, separation and purification, the target carboxylic acid can be obtained.
The second oxidation method is also a common strategy. If there are suitable alcohols or aldehyde compounds, you can use oxidation reagents to oxidize them to carboxylic acids. If alcohols are taken, the oxidation reaction is carried out in an acidic or alkaline medium with a strong oxidant of potassium permanganate or potassium dichromate. During the reaction, attention should be paid to the control of the reaction conditions to avoid excessive oxidation. After the reaction is completed, a series of post-treatment processes, such as extraction, distillation, etc., pure carboxylic acid can be obtained.
Third, the hydrolysis of nitriles is also a good strategy. Choose a suitable nitrile compound and use an acid or base as a catalyst to hydrolyze it. Taking acid catalysis as an example, the nitrile is co-heated with an acid solution, and the nitrile group is gradually hydrolyzed to a carboxylic group. After the reaction, through neutralization, separation and other steps, the desired carboxylic acid is finally obtained.
Fourth, the Grignard reagent method is also feasible. Grignard's reagent is first prepared, and it is obtained by reacting halogenated hydrocarbons with magnesium in anhydrous ether. Then Grignard's reagent reacts with carbon dioxide to form carboxylic salts, which are then acidified to obtain carboxylic acids. This process requires attention to the anhydrous and anoxic reaction environment to ensure the smooth progress of the reaction.
Where this number method has its own advantages and disadvantages, in practical applications, when many factors such as the availability of raw materials, cost, and purity requirements of the product are carefully selected, it can be efficiently synthesized to its 4-carboxylic acid.

Answer: In today's market, the price range of borax varies according to the category, quality, supply and demand status and regional differences.
Borax has a wide range of uses and is used in various fields such as chemical industry, medicine, metallurgy, and building materials. Its categories are industrial grade and pharmaceutical grade.
Industrial grade borax, if traded in the general market, the common price is about a few yuan to a few dozen yuan per kilogram. If its quality is ordinary, when the market supply is abundant and the demand is stable, the price may tend to be low, around five yuan to ten yuan per kilogram; however, if the quality is high, and the market demand is strong, the supply is slightly tight, the price may be about twenty yuan per kilogram.
As for pharmaceutical grade borax, due to strict quality and purity requirements, its price is usually higher than that of industrial grade. The price per kilogram may range from tens of yuan to 100 yuan. If it is high-purity borax that meets strict medical standards, it may reach more than 100 yuan per kilogram.
However, the market changes, and the price is not constant. If the price of raw materials rises and falls, the production process is innovative, or the policy and regulation changes, the price of borax will fluctuate. In order to know the accurate price range, it is also necessary to gain real-time insight into the market conditions and consult relevant suppliers or industry insiders in detail.