Introduction. Carboxylation and alkoxycarbonylation

Landscape design and planning(1,4-butanedicarboxylic acid, Hexanedioic acid, e355) is a food additive of the antioxidant group - a dibasic saturated carboxylic acid (a class of organic compounds whose molecules contain one or more functional carboxyl groups - COOH).

Physicochemical characteristics.

Gross formula: C 6 H 10 O 4.

Structural formula:

H O O O O H

Adipic acid has all the chemical properties characteristic of carboxylic acids. Appearance: correct form white crystals or powder. Melting point 152 °C. Boiling point 337.5 °C. Density 1.36 g/cm3. It is harmless in its effect on the human body. Adipic acid forms salts, most of which are soluble in water. Adipic acid is easily esterified into mono- and diesters, and with glycols it forms polyesters. Adipic acid is a colorless crystalline powder. Disintegrates when heated, releasing volatile vapors of valeric acid and other substances.

Application.

As a raw material in the production of synthetic fibers (polyamides) and polyurethanes;

As a plasticizer in the production of plastics;

In printing for the production of high quality paper;

In the production of esters and dyes;

As the main component various means to remove scale.

Adipic acid is used as a mild acidulant with low hygroscopicity and a sour taste that persists long time, for example: in chewing gum up to 3%; in desserts up to 0.6%; in baking mixtures up to 0.4%; in dry drink mixes up to 1% (in terms of ready-to-drink product).

Acceptable daily consumption– 5 mg/kg body weight per day calculated as adipate ion. MPC in water is 2.0 mg/l, hazard class 3.

E355 is allowed in dry flavored desserts in quantities up to 1 g/kg of product; in powdered mixtures for making drinks at home in quantities up to 10 g/kg; in fillings, finishing semi-finished products for rich bakery products and flour confectionery products, etc. in amounts up to 2 g/kg individually or in combination with other adipates in terms of acid.

Health hazards of adipic acid.

Inhalation: cough, difficulty breathing, sore throat.

Skin: redness.

Eyes: redness, pain.

Adipic acid is low toxic when ingested.

An explosion is possible if it is mixed in powder form with air. In dry form, the substance can be electrostatically charged during vortex movements, pneumatic transportation, pouring, etc.

Receipt.

E355 is obtained by the oxidation of cyclohexane, which occurs in two stages. The drug is also obtained by reacting cyclohexane with nitric acid or ozone. One of the promising production methods is the hydrocaronylation of butadiene. The world produces 2.5 million tons of adipic acid per year.

Adipic acid (Adipic acid, hexanedioic acid, 1,4-butanedicarboxylic acid) belongs to the family of dibasic saturated carboxylic acids. It has good solubility in ethanol and limited solubility in ether, but is sparingly soluble in water. However, most salts (adipates) formed by adipic acid are soluble in water. When adipates are dehydrated, they are converted into adipamides. Adipic acid has all the chemical properties characteristic of the family of carboxylic acids. Reacts with glycols to form polyesters.

Externally, adipic acid is white or colorless crystalline substance density approximately 1.36 g/cc. The melting point of adipic acid is about 153 °C, the decomposition temperature is about 220 °C (±20 °C), and adipic acid boils at 260 °C.

The most common general method for the synthesis of adipic acid in industry is the oxidation of cyclic compounds (cyclohexane)

GOST 10558-80 identifies several types of adipic acid. The table below shows the main characteristics and their compliance with GOST standards.

The guaranteed shelf life of adipic acid is 1 year.

We invite you to pay attention to such raw materials for paint and varnish materials as Adipic acid. This substance is produced in full compliance with current standards and is a high-quality component for paints and varnishes.

Film-forming substances occupy the main place among raw materials for paints and varnishes. They provide the main qualities of the material: its strength, durability, resistance to external influences. Various resins (alkyd, acrylate, epoxy, etc.) and aqueous dispersions of polymers (acrylic, polyurethane) most often act as film-forming agents.

Various pigments are responsible for the final color of the coating. In addition to decorative qualities, pigments can impart paint coating light resistance, electrical conductivity and other useful properties. Paintwork pigments are divided into inorganic (titanium dioxide, zinc oxide, ocher, etc.) and organic (anthraquinone, phthalocyanine, etc.). To reduce the cost of coatings, special filler additives are added to the composition. As a rule, these are substances of natural origin that, if formulated correctly, can improve the quality of the coating.

If you want to give the final coating elasticity, plasticizers (phthalates, phosphates) are added to the paintwork composition. To speed up the drying process, driers are added to paints (true - salts of carboxylic acids and promoters - salts of barium, calcium, etc.).

Hexanedioic or adipic acid (e355) is a food additive of the antioxidant group.

From a physical point of view, the substance is colorless crystals. Adipic acid is on the list of additives approved by the European Union, however, this moment its use is prohibited in many countries, since the acid is still at the testing stage.

Preparation of adipic acid

Industrially, e355 is produced mainly by two-stage oxidation of cyclohexane. Initially, a mixture of cyclohexanone and cyclohexanol is obtained, which is then separated by rectification. Cyclohexanone is subsequently used to produce caprolactam, and cyclohexanol is oxidized with 40-60% nitric acid to produce adipic acid. Its yield using this method of production is about 95%.

There is another promising method for producing adipic acid by hydrocarbonylation of butadiene. Today, about 2.5 million tons of adipic acid are produced worldwide.

Applications of adipic acid

In those states where the food additive E355 is approved for use, it is used as an acidity regulator in the preparation of caramel candies, drinks and other food products to maintain the required pH level. The additive is added to some types of dry flavored desserts, but in a strictly prescribed amount - up to 1 g/kg finished products.

In jelly-like desserts, the permissible level of adipic acid is no more than 6 g/kg, and in powder mixtures for preparing drinks, 4 g/kg is allowed. The E355 additive is often added to fillings for bakery and confectionery products.

Besides Food Industry adipic acid is widely used in chemical industry. Thus, about 90% of all acid produced is used as a raw material in the production of polyhexamethylene adipinamide, as well as its esters and polyurethanes. Use acid to remove material remaining after filling the joints between ceramic tiles, as well as in the production of products intended for descaling.

Effect on the human body

Naturally, in excessively high dosages, any food additives can harm human health. Since the current effect of a food additive on human body has not been fully studied, its use is allowed only in a strictly defined concentration.

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Adipic acid

Chemical formula of the product: C 6 H 10 O 4 / HOOC(CH 2) 4 COOH

Product trade names:

• Adipic acid

• 1,4-Butanedicarboxylic acid
• 1,6-Hexanedioic Acid
• Acifloctin
• Hexanedioic acid
• E-355

Product Description:

Adipic acid (also called hexanedioic acid) is a white crystalline compound di carboxylic acid with straight chain C6; Slightly soluble in water and soluble in alcohol and acetone. Almost all commercial adipic the acid is obtained from cyclohexane through two successive oxidation processes. The first oxidation is the reaction of cyclohexane with oxygen in the presence of cobalt or manganese catalysts at a temperature of 150-160 °C, which form cyclohexanol and cyclohexanone. The intermediates are then further reacted with nitric acid and air with or without a catalyst (copper or vanadium). Cyclohexane can be prepared by hydrogenating benzene. There are other methods, such as reactions using phenol, butadiene and various fats as starting materials. Consumption adipic acid Almost 90% is associated with the production of nylon by polycondensation with hexamethylenediamine. Nylon, which has a protein-like structure, is further processed into fibers for use in carpeting, car tires and clothes. Adipic acid used in the production of plasticizer and lubricant components. Used in the production of polyester polyols for polyurethane systems. Adipic acid food grade is used as a gelling aid, acidifier, leavening agent and buffering agent. Adipic acid has two carboxylic acids, -COOH, groups that can produce two kinds of salts. Its derivatives, acyl halides, anhydrides, esters, amides and nitriles are used in the preparation of target products such as flavors, internal plasticizers, pesticides, dyes, textile treatments, fungicides and pharmaceuticals through further substitution reactions, catalytic reduction, metallization Hydride reduction, diborane reduction, keto formation with organometallic reagents, electrophilic coupling in oxygen and condensation. A dicarboxylic acid is a compound containing two carboxylic acid groups, -COOH. Examples with a straight chain are given in the table. General formula is HOOC(CH2)nCOOH, where n is oxalinic acid, n = 1 for malonic acid, n = 2 for succinic acid, n = 3 for glutaric acid, etc. In the substitutive nomenclature of their name Formed by adding -dioic" as a suffix to the name of the parent compound. They can give two types of salts, since they contain two carboxyl groups in their molecules. Range of lengths carbon chains range from 2, but longer than C 24, very rarely. The term long chain refers usually to C 12 to C 24. Carboxylic acids have industrial applications directly or indirectly through halides, esters, salts and anhydride forms, polymerization and. etc. Dicarboxylic acids can produce two types of salts or esters, since they contain two carboxyl groups in one molecule. There are almost endless esters produced from carboxylic acids. acids and alcohols. Carboxylic acid esters are used in both a variety of and indirect applications. Lower chain esters are used as flavoring base materials, plasticizers, solvent carriers, and coupling agents. Higher chain compounds are used as components in metal working fluids, surfactants, lubricants, detergents, lubricants, emulsifiers, wetting agents, textile treatments and emollients. They are also used as intermediates for the preparation of various target compounds. Nearly infinite esters provide a wide range of viscosities, specific gravity, vapor pressure, boiling point and other physical and Chemical properties to select the proper application.

Physico-chemical properties of Adipic acid.

Transportation and storage of Adipic acid:

Crystalline adipic acid tends to form conglomerates. Parameters that can influence the formation of conglomerates include not only storage time, but also humidity, temperature and particle size. It is recommended that the melted adipic acid subject to storage due to its parameters. Store and transport under nitrogen atmosphere. The main risk of handling adipic acid there is a danger of explosion. Adipic acid dust suspended in air can ignite at temperatures of 500-550 °C. According to the Bureau of Mines, dust adipic acid has an explosion severity index of 1.9 and a relative explosive rating. Khrustalnaya adipic acid must be stored in a nitrogen atmosphere or in a mixture of nitrogen and air with an oxygen content of less than 10%. During pneumatic transport adipic acid Both nitrogen and air can be used. However, in the latter case, precautions must be taken to avoid the risk of dust ignition. In particular, transport equipment must have explosion openings to dissipate the force of any possible explosion, and all equipment must be carefully grounded to prevent static charges. Solid adipic acid and her aqueous solutions attack mild steel even at room temperature, but have no significant effect on stainless steel and aluminum.

Product Application Areas:

1. In medicine. Adipic acid was incorporated into controlled-release prescription drug matrix tablets to provide pH-independent release for both weakly basic and weakly acidic drugs. It was also included in polymer coating hydrophilic monolithic systems to modulate the pH of the intracellular layer, which led to the release of hydrophilic medicine zero order. Disintegration at intestinal pH of enteric shellac is reported to be improved when adipic acid is used as a pore-forming agent without affecting release in an acidic environment. Other controlled-release formulations include adipic acid to produce an end-burst release profile. Adipic acid used to make bisobrin antifibrinolytic.
2. In the food industry. Small but significant amounts adipic acid used as a food ingredient as a flavoring and gelling agent. It is used in some calcium carbonate antacids to make them tart. As an acidulant in baking powders, it avoids the undesirable hygroscopic properties of tartaric acid. Adipic acid, rare in nature, occurs naturally in beets, but is not an economical source of commerce compared to industrial synthesis.
3. At home. Adipic acid buy and used in the production of a wide range of products for use in homes, such as carpeting, home furnishings, and fragrances.
4. In an office environment. Adipic acid buy and use in office production floor coverings and furniture.
5. In the automotive industry. Adipic acid used in the production of a wide range of lightweight automotive parts, as well as seat upholstery and car mats.
6. In everyday recreational activities. Adipic acid used in the production of specialized footwear, recreational equipment, as well as specialized recreational clothing.
7. A dipic acid and is used in the production of nylon 6-6, which is widely used throughout the world.
8. Adipic acid used in the production of a wide range of adsorbents and absorbents.
9. Adipic acid used in the production of finishing materials.
10. Adipic acid used in the production of lubricants and lubricants.
11. Hexanedioic acid used in the production of plasticizers.
12. Hexanedioic acid used in the manufacture of paints and specialized paint additives.
13. Hexanedioic acid used as a solids separating agent in industrial production.

About 3 million tons of adipic acid are produced annually.

About 10% is used in the food industry in Canada, EU countries, the USA and many CIS countries.

Foods rich in adipic acid:

Juices from concentrates Fruit jelly

industrial production

Chewing gum

General characteristics of adipic acid

Adipic acid, or hexanedioic acid as it is also called, is a food additive E 355 that acts as a stabilizer (acidity regulator), acidifier and leavening agent. Adipic acid appears as colorless crystals with a sour taste. It is produced chemically

when cyclohexane reacts with nitric acid or nitrogen. A detailed study of all the properties of adipic acid is currently underway. Determined that this substance – low toxic. Based on this, the acid is classified as a third safety class. According to

State Standard (dated January 12, 2005) adipic acid has minimal harmful effects on humans. It is known that adipic acid has a positive effect on the taste of finished products. Affects the physical and chemical properties of the dough, improves appearance

Used in the food industry:

• for improvement taste qualities and physical and chemical indicators of finished products;
• for longer storage of products, to protect them from spoilage, is an antioxidant.

In addition to the food industry, adipic acid is also used in light industry. It is used to produce various artificial fibers, such as polyurethane.

Manufacturers often use it in household chemicals. Adipic acid esters are included in skin care cosmetics.

Adipic acid is also used as a component in products designed to remove scale and deposits in household equipment.

Daily human requirement for adipic acid:

Adipic acid is not produced in the body, and it is also not a necessary component for its functioning. The maximum permissible daily dosage of acid is 5 mg per 1 kg of weight.

The maximum permitted dosage of acid in water and drinks is no more than 2 mg per 1 liter.

The need for adipic acid increases:

• Adipic acid is not a vital substance for the body. It is used only to improve the nutritional quality and shelf life of finished products. The need for adipic acid is reduced:;
• V
• childhood

contraindicated during pregnancy and breastfeeding;

during the adaptation period after an illness. Absorption of adipic acid To date, the effect of the substance on the body has not been fully studied. It is believed that consuming this in limited quantities

food supplement

Can.

The acid is not completely absorbed by the body: a small part of this substance is broken down in it. Adipic acid is excreted from the body in urine and exhaled air. Beneficial properties of adipic acid and its effect on the body:

Useful properties

for the human body has not yet been discovered. Adipic acid has a positive effect only on the preservation of food products and their taste characteristics. Factors influencing the content of adipic acid in the body Adipic acid enters our body along with food, as well as when using some household chemicals.

The acid content is also affected by the field of activity. High concentration of the substance entering Airways

, can irritate mucous membranes. A large number of For health reasons, it is recommended to take all necessary precautions at the enterprise and adhere to sanitary standards.

The maximum permissible value of the substance in the air is 4 mg per 1 m 3.

Signs of excess adipic acid