What are the raw materials for the production of adipic acid, the preparation of adipic acid

1. The raw material for the production of adipic acid is nitric acid oxidation ka oil, copper-vanadium.

2. Process: After the oxidation product of KA oil is distilled to nitric acid, and then through two-stage crystallization and refining, high-purity adipic acid can be obtained.

3. Adipic acid is an important organic diacid, mainly used in the manufacture of nylon 66 fiber and nylon 66 resin, polyurethane foam, which has a wide range of uses: in the organic synthesis industry, it is the basic raw material of adiponitrile and hexamethylenediamine, and can also be used for the production of lubricants, plasticizer dioctyl adipate, and can also be used in medicine.

In 1937, the DuPont Company of the United States used nitric acid to oxidize cyclohexanol (produced by hydrogenation of phenol), and first realized the industrial production of adipic acid. In the 60s, the industry gradually switched to cyclohexane oxidation, that is, cyclohexane was first made from cyclohexane as an intermediate product cyclohexanone and cyclohexanol mixture (i.e., ketone alcohol oil, also known as KA oil), and then nitric acid or air oxidation of KA oil was carried out. The nitric acid oxidation KA oil method generally uses an excess concentration of 50% 60% nitric acid through a two-stage reactor in series.

The catalyst used in the reaction is copper-vanadium (copper vanadium, temperature 60 80, pressure . The yield is 92% to 96% of the theoretical value. After the oxidation product of KA oil is distilled to nitric acid, and then through two-stage crystallization and refining, high-purity adipic acid can be obtained.

The air oxidation method uses copper acetate and manganese acetate as catalysts and acetic acid as solvents to directly oxidize KA oil with air. Generally, two-stage reactors are used in series: the first-stage reaction temperature is 160 175, pressure gauge pressure), and the reaction time is about 3h; The second stage reaction temperature is 80, pressure gauge pressure), and the reaction time is about 3h.

The oxidation product is refined by two-stage crystallization, and the solvent of ** can be recycled after treatment. The selectivity of this method is comparable to that of the nitric acid method, and there is no strong corrosion problem of the nitric acid method, but the reaction time is four times that of the nitric acid method, so it is still rarely used.

Mainly cyclohexane. A mixture of cyclohexanone and cyclohexanol is made from cyclohexane, and then the mixture is oxidized with nitric acid.

The preparation method of adipic acid is as follows:

One-step oxidation of cyclohexane:

Cyclohexane was used as raw material, acetic acid was used as solvent, and cobalt and bromide were used as catalysts in 2MP. and 90 reactions for 10 to 13 h. The yield is 75%.

Cyclohexane step-by-step oxidation method:

The preparation of KA oil can be directly oxidized with air at 145 180 °C, with a yield of 70% to 75%. Metaboric acid can also be used as a catalyst for air oxidation at 165 °C, with a yield of up to 90% and an alcohol-to-ketto ratio of 10:1; The reactants are treated with hot water, which can hydrolyze and stratify esters, and the aqueous layer is **boric acid, which is dehydrated into metaboric acid and recycled; The organic layer is saponified with caustic soda and the acid is removed, and the alcohol ketone mixture is obtained after distillation of **cyclohexane.

Uses of Adipic Acid:

Adipic acid is the most valuable diacid in aliphatic diacids. Adipic acid has the general properties of aliphatic diacids, including salt formation reaction, esterification reaction, amidation reaction, etc. The main uses of adipic acid are as a raw material for three major categories of products, namely:

synthetic nylon 66 salts to make polyamide resins and fibers, with nylon 66 being the largest end market for adipic acid; synthetic polyester polyols for the production of polyester-type polyurethanes; Adipate diester plasticizer. It can also be used in the production of advanced lubricants and food additives.

Adipic acid preparation process: C4 olefin method.

1. C4 olefin method: It is based on the active ingredients n-butene, butadiene and isotonic dena in the mixed C4 fraction as raw materials, and air (or oxygen), under the action of V2O5-P2O3 catalysts, through gas-phase oxidation reaction to generate maleic anhydride, in which n-butene is first dehydrogenated to generate butadiene during the reaction process, and then oxidized to generate maleic anhydride.

2. Adipic acid: also known as fatty acid, is an important organic diacid, the structural formula is Hooc(CH2)4COOH. It can undergo salt formation reaction, esterification reaction, amidation reaction, etc., and can be polycondensed with dibasic amines or diols into polymers.

Adipic acid is a dicarboxylic acid of great industrial significance, which plays an important role in chemical production, organic synthesis industry, medicine, lubricant manufacturing, etc., and its output ranks second among all dicarboxylic acids.

Third, the main uses:

Adipic acid is mainly used as a raw material for nylon 66 and engineering plastics, and is also used in the production of various ester products, and is also used as a raw material for polyurethane late ester elastomers, and as an acidifier for various foods and beverages, and its effect is sometimes better than that of citric acid and tartaric acid.

Adipic acid is also a raw material for medicines, clumbus yeast purification, pesticides, adhesives, synthetic leather, synthetic dyes and fragrances.

Adipic acid has a soft and persistent sour taste, and the pH value changes little in a large concentration range, making it a good pH regulator. GB2760-2007 stipulates that the maximum amount of this solid beverage is; It can also be used for jelly and jelly powder, and the maximum amount used for jelly is; When used for jelly powder, the amount can be increased according to the preparation multiple.

One-step oxidation of cyclohexane:

With cyclohexane as raw material, acetic acid as solvent, cobalt and bromide as catalysts, the reaction was carried out at 2 megapascals and 90 degrees Celsius for 10 to 13 hours. The yield is 75 out of 100.

Cyclohexane step-by-step oxidation method:

Oxidation of KA oil by excess 50 to 60 percent nitric acid in a two-stage series reactor at 60 to 80 degrees Celsius and to MPa. The catalyst is copper and vanadium, and the yield is 92% to 96% of the theoretical value. After the reactant is evaporated from nitric acid, it can be refined by two crystallizations to obtain high-purity adipic acid.

Categories: Education, Science, >> Science & Technology.

Problem description: Why is the droplet acceleration of cyclohexanol strictly controlled in the reaction, and why is it necessary to keep the reactants in a boiling state during the reaction?

Why should some experiments be pre-heated when adding the last reactant? Why is it that in some experiments with violent reactions, the feeding speed is slowed down at the beginning, but after the reaction starts, the feeding speed can be appropriately accelerated, and what is the reason?

It's best to introduce if there is a page to introduce this experiment.,Thank you!!

Analysis: In order, step by step, Sissy.

1. Why must the reaction strictly control the droplet acceleration of cyclohexanol, and why should the reactants be kept in a boiling state during the reaction?

Controlling the droplet acceleration of cyclohexanol is the key to the preparation of adipic acid experiments. Because this reaction is a strongly exothermic reaction, it is necessary to wait for a small amount of cyclohexanol added to the reaction flask to be completely active before continuing to add dropwise. If the dropwise addition is too fast, the reaction is too violent and uncontrollable, which will cause the reaction solution to rush out of the flask and cause an accident.

The drops are too slow, the reaction proceeds slowly, and it takes too long. Therefore, the speed of dropwise addition of cyclohexanol should be controlled during operation to maintain the reaction solution in a slightly boiling state.

2. Why should some experiments be preheated after adding the last reactant?

Activation energy is required for both endothermic and exothermic reactions. For some reactions with high activation energy (which still cannot reach its activation energy at room temperature), it is necessary to supply energy through external heating to achieve the required activation energy.

3. Why is the feeding speed slow at the beginning of some experiments with violent reactions, but after the reaction starts, the feeding speed can be appropriately accelerated, and what is the reason?

Organic reactions are generally exothermic reactions, but in order to overcome the activation energy barrier, some organic reactions need to be heated to a certain temperature before they can be carried out. Some organic synthesis experiments preheat the substrate before adding the last reactant and then add the last reactant in batches, which allows the reaction to proceed smoothly and easily controlled. Otherwise, if all the reactants are mixed and then heated, a large amount of heat or gas will be suddenly released after the reaction starts, which is difficult to control and can easily cause accidents.

In some experiments with violent reactions, the feeding speed should also be very slow at the beginning due to the slow progress of the reaction, so as to avoid excessive accumulation of reactants that lead to the sudden release of a large amount of heat or gas after the reaction is initiated, or cause other side reactions; After the reaction starts, due to the fast reaction speed, the added materials will react quickly, and there will be no phenomenon of reactant accumulation, so the feeding speed can be appropriately accelerated.

Adipic acid hooc (CH2) 4

COOH is commonly known as fatty acid, and the white crystals are at the end of this part.

Industrial uses of adipic acid.

Adipic acid is the main monomer of the synthetic fiber nylon 66.

Adipic acid is the main raw material of nylon engineering plastics.

Adipic acid is the main raw material for the synthesis of terrestrial polyurethane foams, synthetic leather (PU), synthetic rubber and film.

Adipic acid can be used as an acidifier for food products, ester plasticizers and textile treatment agents.

Adipic acid can also be used in the production of pharmaceuticals, pesticides, spices, adhesives and fluxes.

Dioctyl adipate is also a type of adipic acid, dioctyl adipate honyanszCN is a kind of plasticizer, and the raw material for production is nitric acid oxidized ka oil, copper-vanadium system.

Adipic acid, also known as fatty acid, is an important organic dibasic acid, which can undergo salt reaction, esterification reaction, amidation reaction, etc., and can be polycondensed with dibasic amines or diols into polymers. Adipic acid is a dicarboxylic acid of great industrial significance, which plays an important role in chemical production, organic synthesis industry, medical medicine, lubricant manufacturing, etc., and its output ranks second among all dicarboxylic acids.