The method of producing pentaerythrite

 

(57) Abstract:

Use: in the manufacture of paint resins, drying oils, in particular in the method of producing pentaerythritol. The inventive product is pentaerythritol, the yield of 85.5 - 86 mol.%, the content of the main substance of the 98.9 99%, so pl. 256 - 258oWith content dipentaerythritol of 0.3 - 0.4%. Reagent 1: formaldehyde. Reagent 2: acetaldehyde. Reaction conditions: in an aqueous medium in the presence of calcium oxide and boric acid in the amount 0,115 mol per 1 mol of acetaldehyde or borax in the amount of 0.019 mol per 1 mol of acetaldehyde. Preferably the mixture is maintained at 25 - 30oTo the content of aldehydes 2.5 to 3 wt.%. The ratio of formaldehyde and acetaldehyde is 5.4 : 1. table 1.

The invention relates to organic chemistry, namely to improve the method of producing pentaerythritol (PE) with simultaneous separation of calcium formate.

A method of obtaining PE [1] condensation of formaldehyde with acetaldehyde in the presence of catalyst of alkali metal hydroxide, followed by separation of the target product and further processing the mixture of metal hydroxide with hydrosulfite sodium.

The disadvantages of this method what is dependent on the melting stage condensation is delayed due to the filing of acetaldehyde 90-100 minutes

Closest to the present invention is a method of producing pentaerythritol interaction of acetaldehyde with formaldehyde in the presence of calcium oxide in water at a temperature of 0-50aboutAnd the concentration of formaldehyde in the reaction solution 12-18% and the molar ratio of acetaldehyde and formaldehyde is from 1:7 to 1:10 and the molar ratio of acetaldehyde and calcium hydroxide from 1:0.7 to 1:1 [2] as inhibitor used copper ions. Excess formaldehyde Argonauts to a residual content in the solution of 0.15-0.7 percent Distillation of free formaldehyde from the reaction solution is held at a temperature of 125 to 150aboutC and a pressure of 1.5 to 6 ATM, the concentration of pH in the range of 5-7, at constant volume and in the presence of calcium carbonate or bicarbonate calcium.

The disadvantages of this method is that

the necessary stage of distillation of the excess formaldehyde;

the presence of residual formaldehyde contributes to the solubility of pentaerythritol in the mother solution and the resulting reduced product output;

acetaldehyde is served 1.5 h, which slows down the process and reduces the content of the state tobacco monopoly is Noah environment;

the blue hue of the finished pentaerythritol, because as an inhibitor taken copper;

in this way it is impossible to obtain both calcium formate and pentaerythritol grade a and B.

The aim of the invention is to obtain simultaneously pentaerythritol grade a and B and of calcium formate, increase yield, reduce energy consumption by reducing process, reducing sugars, color enhancement, which is especially important when using pentaerythritol in the paint industry.

This goal is achieved using an additive boric acid in the amount 0,115 mol or 0,0187 mol of borax per 1 mol of acetaldehyde and aging the reaction mixture at a temperature of 25-30aboutTo the content of aldehydes of 2.5-3% the Use of borax allows to obtain the same effect as the application of boric acid, also slightly increases the yield of pentaerythritol, reduced consumption of calcium oxide and sulfuric acid.

The features distinguishing the claimed method of producing pentaerythritol and calcium formate from the prototype, have been identified in other technical solutions in the study of the field of production of pentaerythritol and calcium formate, which allows SDE is pentaerythritol and calcium formate is carried out as follows.

P R I m e R 1. In the reactor when operating the mixer load 2743 l of cold water, 1545 kg chilled formalin (formaldehyde content of 36.7 wt. and 154 kg of acetaldehyde. When the temperature of the 13aboutWith 912 kg of milk of lime with a Cao content of 13.7 wt. and condensation heat the solution to 60aboutC. After complete disappearance of the aldehyde, the reaction mass is neutralized and partly precipitated calcium ions 157 kg of sulfuric acid (concentration of 75%) to the content of calcium ions in a solution of 1.3 wt. Gypsum is separated and the filter by evaporation under vacuum and subsequent centrifugation receive technical pentaerythritol. After recrystallization of technical pentaerythritol from hot water to obtain the target product with the following quality indicators:

The melting pointaboutWITH 250-251

The content of sugar

substances, wt. 0.04

The content of monument-

eritria, wt. 98,5

The content of dipentaerythritol,

wt. 0,8

The hydroxyl content

groups, 49,3

Output, mol. 84,0

The mother liquor in the amount of 1,600 kg neutralize 235 kg of milk of lime with a Cao content of 13.7 wt.

From neutralized mother liquor at 80aboutWith the vacuum of othona the th solution after separation of the calcium formate is cooled to 25aboutWith and additionally allocate technical pentaerythritol (60 kg).

P R I m m e R 2. In the reactor when operating the mixer load 3020 kg of cold water 1527 kg chilled formalin (formaldehyde content 36.9 wt.) and 154 kg of acetaldehyde. When the temperature of the 12aboutTo download 675 kg of milk of lime with a Cao content of 18.5 wt. The ascent begins, the temperature of the reaction mixture due to the heat of reaction, while achieving the 25aboutWith the jacket of the reactor is fed cold water to stop the rise of temperature. Cooling is carried out until the content of aldehydes 2.5 wt. and begin heating the reaction mass to 60aboutC. After complete disappearance of the aldehyde, the reaction mass is neutralized and partly precipitated calcium ions 169 kg of sulfuric acid (concentration of 75%) to the content of calcium ions in a solution of 1.3 wt. Gypsum is separated and the filter by evaporation under vacuum and subsequent centrifugation receive technical pentaerythritol.

After recrystallization of technical pentaerythritol from hot water to obtain the target product with the following quality indicators:

The melting pointaboutWITH 254-256

The content of sugar

substances, wt. 0,03

The content of monument-
Output, mol. 85,5

The selection of calcium formate and pentaerythritol from the mother liquor as in example 1.

P R I m e R 3. In the reactor when operating the mixer load 2919 l of cold water, 25 kg of boric acid, 1532 kg chilled formalin (formaldehyde content 37,0 wt.) and 154 kg of acetaldehyde. When the temperature of the 14aboutTo download 764 kg of milk of lime with a Cao content of 16.2 wt. The condensation solution is heated to 60aboutC. After complete disappearance of the aldehyde, the reaction mass is neutralized and partly precipitated ions CA 176 kg of sulfuric acid (concentration of 75% ) to the content of calcium ions in a solution of 1.5 wt. Gypsum is separated and the filter by evaporation under vacuum and subsequent centrifugation receive technical product.

After recrystallization of technical pentaerythritol from hot water to obtain the target product with the following quality indicators:

The melting pointaboutWITH 256-258

The content of monument-

eritria, wt. 99,0

The content of dipentaerythritol,

wt. 0,3

The hydroxyl content

groups, wt. 49,5

Output, mol. 85,5

The selection of calcium formate and pentaerythritol from the mother liquor of analogically, 1540 kg chilled formalin (formaldehyde content to 36.8 wt.) and 154 kg of acetaldehyde. At the temperature of 15aboutTo download 809 kg of milk of lime with a Cao content of 15.7 wt. The ascent begins, the temperature of the reaction mixture due to the heat of reaction. When the temperature reached 25aboutWith the jacket of the reactor is fed cold water to stop the rise of temperature. Cooling is carried out until the content of acetaldehyde of 3.0 wt. and begin heating the reaction mass to 60aboutC. After complete disappearance of the aldehyde, the reaction mass is neutralized and partly precipitated calcium ions 175 kg of sulfuric acid (concentration of 75%) to the content of calcium ions in a solution of 1.5 wt. The gypsum is separated from the filter by evaporation under vacuum and subsequent centrifugation receive technical pentaerythritol.

After recrystallization of technical pentaerythritol from hot water to obtain the target product with the following quality indicators:

The melting pointaboutWITH 256-258

The content of monument-

eritria, wt. 99,0

The content of dipentaerythritol,

wt. 0,3

The hydroxyl content

groups, wt. 49,5

Output, mol. 86,0

P R I m e R s 5-12. In examples 5-9, the processes on which the reamers are given in the table.

The pentaerythritol obtained by the proposed method corresponds to GOST 9286-89 prepared for spenceley, and for use in paint and varnish production, in which important indicators is the color of the product.

1. The METHOD of producing PENTAERYTHRITE followed by separation of the calcium formate, including the condensation of formaldehyde with acetaldehyde in an aqueous medium in the presence of calcium oxide and neutralization of sulfuric acid, wherein the process is conducted in the presence of boric acid in the amount 0,115 moles per 1 mole of acetaldehyde or borax in the amount of 0,019 moles per 1 mole of acetaldehyde.

2. The method according to p. 1, characterized in that the mixture is maintained at 25 - 30oTo the content of aldehydes of 2.5 - 3 wt. %.

3. The method according to PP.1 and 2, characterized in that the formaldehyde charge in the amount of 5.4 Mols per 1 mol of acetaldehyde.

 

Same patents:

The invention relates to the technology of polyols, in particular pentaerythritol used in paint and other industries

The invention relates to organic chemistry, namely to improve the method of producing pentaerythritol (PE), used in the manufacture of explosives, the simultaneous achievement of calcium formate used in the pulp and paper, leather industries, construction and agriculture

FIELD: concentration of pentaerythrite formate mother liquors in the multi-case evaporation plant with vertical heat exchange tubes for production of high-quality lacquers, additives for oils and other products.

SUBSTANCE: proposed method includes concentration of pentaerythrite formate mother liquors at the first stage by evaporation to saturation state by pentaerythrite and crystallization of pentaerythrite from saturated solution; concentration at the first stage is performed at film flow solution; crystallization is carried out at two stages at forced circulation of suspension thus formed. Secondary vapor is divided into two flows after first stage of evaporation: one flow is delivered to the first stage of crystallization and second flow is delivered to the second stage of crystallization. At the second stage of crystallization boiling point of suspension is maintained at temperature of 45-53°C which is below that at the first stage by 7-20°C. Evaporation plant for processing the pentaerythrite formate mother liquors has two stages of evaporators connected in succession in way of flow of vapor and solution and provided with vertical tubes. Second stage of evaporation plant is just crystallizer provided with circulating loop with pump and vapor separator connected with final condenser by means of vapor pipe line. First stage consists of film liquid flow evaporator; second stage is provided with additional crystallizer with circulating loop and pump and additional condenser connected with vapor separator of additional crystallizer; it is also provided with non-condensable gas discharge unit. Last evaporator of the first stage is provided with additional pipe line for discharge of secondary vapor which is communicated with heating chamber of additional crystallizer. Solution volume of additional crystallizer exceeds that of the first one by 1.5- 2.5 times.

EFFECT: improved quality of crystalline products; increased degree of extraction of pentaerythrite from solution; increased rate of processing the solutions.

6 cl, 1 dwg, 1 tbl

FIELD: chemistry.

SUBSTANCE: present invention relates to a method for synthesis of pentaerythritol and dipentaerythritol, involving reaction of acetaldehyde with formaldehyde in the presence of sodium hydroxide, purification of the reaction solution through distillation of excess formaldehyde, evaporation and crystallisation of technical pentaerythritol, washing the residue, recrystallisation of technical pentaerythritol, separation of the residue from the solution and drying commercial-grade pentaerythritol and treatment of the product after drying. After drying the product is treated through separation, thereby extracting the pentaerythritol fractions most contaminated with non-volatile impurities of dipentaerythritol and cyclic formalin, and the extracted fractions are processed by leaching pentaerythritol with demineralised water at 10-80C and ratio of liquid phase to solid phase equal to (5.5-8)/1, and subsequent separation of the formed pentaerythritol solution and dipentaerythritol precipitate and taking the pentaerythritol solution to the technical pentaerythritol recrystallisation step.

EFFECT: method enables to obtain pentaerythritol with low content of dipentaerythritol and cyclic formalin impurities, as well as recycling of dipentaerythritol.

6 cl, 1 tbl, 7 ex

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of processing filtrate wastes from production of pentaerythritol, containing (wt %): 32-37.81 sodium formate, 22-27 pentaerythritol, 10-11 cyclic monoformals, 2-3 dipentaerythritol, as well as pentaerythritol derivative impurities, to obtain technical pentaerythritol and sodium formate. The method involves treatment of the filtrate with an extraction agent, followed by separation and recycling of the obtained liquid and solid phases. Treatment is carried with water in water/filtrate ration equal to (0.5-1.0)/1 and temperature 15-25C, followed by taking the washed off residue to the evaporation and crystallisation step to obtain technical pentaerythritol and the filtrate solution for evaporation and crystallisation to obtain sodium formate.

EFFECT: efficient method of processing waste filtrate from production of pentaerythritol.

2 tbl, 1 ex

FIELD: process engineering.

SUBSTANCE: invention relates to organic synthesis, particularly, to method of processing commercial sodium pentaerythritol and formiate and may be used in chemical industry, paint-and-varnish industry, etc. Method of processing commercial sodium pentaerythritol and formiate mother solution consists in extracting pentaerythritol and liquid phase separation. Mother solution is diluted by water to content of sodium formiate of 30-32%. Then produced solution is heated to at least 60C and mixed at said temperature for at least 4 hours at the rate of 900-1100 rpm. Then, produced suspension is filtered in vacuum filter to precipitate pentaerythritol and separate filtrate containing sodium formiate to extract the latter therefrom.

EFFECT: separate crystallisation of sodium pentaerythritol and formiate.

2 cl, 1 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing pentaerythritol, involving condensation of formaldehyde with acetyldehyde in the presence of sodium hydroxide, rectification and evaporation of the condensed solution, vacuum crystallisation, filtration, washing the obtained technical pentaerythritol, recrystallisation, filtration and drying the pentaerythritol. The formaldehyde is used in form of a mixture of formalin and paraformaldehyde, where the paraformaldehyde constitutes up to 1/5 of the total amount of formaldehyde in the reaction mixture, the components being in the following molar ratio: acetaldehyde 1; formaldehyde 8.4-8.5; sodium hydroxide 1.15-1.20; water 70-72.

EFFECT: method increases efficiency of the process while ensuring high quality of the ready product.

1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing pentaerythritol which is used in production of lacquer, plastic and explosives. The method involves condensation of formaldehyde with acetaldehyde in the presence of sodium hydroxide, crystallisation, filtration and drying the pentaerythritol. The formaldehyde source used is paraformaldehyde in form of granules, into which water is added at temperature 402C and stirred for 4.5-5.5 minutes. Paraformaldehyde then undergoes preliminary dissolution in an alkaline sodium hydroxide solution, said paraformaldehyde being taken in amount of 30% of the total weight of sodium hydroxide, for 15-16.5 minutes at temperature 40-45C. Further, acetaldehyde cooled to -100.1C and a residual amount of sodium hydroxide are added under cooling conditions, and pulled out for 15 minutes while gradually raising temperature of the condensed solution to 60C. Formic acid is added to the condensed solution until pH 6.5 is achieved.

EFFECT: high effectiveness of the process while ensuring the required quality of the product.

1 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of purifying raw polymethylol, which contains polymethylol of formula (I), as well as a hydroxy acid of formula (IV). According to the present method, raw polymethylol is obtained in a multistep process, wherein at step (a) alkanals react via aldol condensation with formaldehyde in the presence of tertiary amines as catalyst to form methylol alkanals of formula (II). Further, at step (b), the reaction mixture obtained at step (a) is divided by distillation into a still residue primarily containing compounds of formula (II) and a head stream containing low-boiling components. The stream coming from the bottom from step (b) is hydrogenated at step (c). The stream coming from step (c) is then distilled at step (d). Low-boiling components from the stream coming from step (c) are separated, and purification is carried out in a distillation column, wherein the bottom of the distillation column is connected to at least one evaporator with a short dwell time. In formulae , , R in each separate case independently denotes a methylol group or an alkyl group with 1-22 carbon atoms or an aryl group or an arylalkyl group with 6-22 carbon atoms.

EFFECT: method reduces losses in output of polymethylol.

12 cl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of distilling an aqueous polymethylol mixture containing a polymethylol of formula

,

a tertiary amine, water, as well as an adduct of a tertiary amine and formic acid (amine formate). According to the disclosed method, distillation is carried out in a distillation column equipped with a condenser, the lower part of the column being connected to an evaporator, wherein temperature in the lower part of the column is higher than the evaporation temperature of the monoether of formic acid and polymethylol (polymethylol formate) formed during the distillation process. In formula (I), R in each case independently denotes another methylol group or an alkyl group with 1-22 carbon atoms or an aryl or aralkyl group with 6-22 carbon atoms.

EFFECT: method enables to obtain polymethylols with low content of polymethylol formate.

14 cl, 4 ex

FIELD: chemistry.

SUBSTANCE: water solution of sodium salt: nitrate, or halogenide, or their mixture, with the concentration from 10 wt % to the concentration below the saturation line, and with the temperature, which ensures obtaining a mixture with the temperature of 20-40C, when it is mixed with the heated mother liquor, is introduced into the hot mother liquor, which has the technological temperature of 90-100C; the mixture is exposed with mixing for 20-60 minutes, with the following separation of the precipitated sediment of solid pentaerythrite from the liquid salt solution. The said mother liquor and water solution of the said sodium salts are taken in a weight ratio in such a way that the concentration of sodium formiate in the mother liquor after mixing constitutes 15-30 wt %.

EFFECT: method efficiency is achieved due to the reduction of the process time and increased degree of solid pentaerythrite extraction, with the simultaneous creation of the wasteless technology with obtaining two target products.

3 cl, 4 ex

FIELD: technological processes.

SUBSTANCE: invention relates to organic synthesis, particularly to processing of pentaerythritol-formiate mother solutions, and can be used for producing sodium formiate. Method of extracting sodium formiate from pentaerythritol-formiate mother solution involves a step of extracting sodium formiate from mother solution, obtained during production of pentaerythritol, with separation of liquid phase. Separated liquid phase in form of solution containing pentaerythritol with impurities and sodium formiate on the edge of saturation at temperature of 955 C is fed into vessel, mother solution, obtained during production of pentaerythritol, is added at temperature of 455 C, mixture temperature is brought to 55-65 C, mixture is held at this temperature until formation of crystals of pentaerythritol with size of not less than 150 mcm. Obtained suspension is filtered to separate released crystals of pentaerythritol and impurities. Remaining solution of sodium formiate is returned to the step of sodium formiate extracting from mother solution, obtained during production of pentaerythritol.

EFFECT: invention allows to increase efficiency of the process by increasing the amount of sodium formiate, obtained at processing of pentaerythritol-formiate mother solution.

1 cl, 3 tbl, 3 ex

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