The method of producing pentaerythritol

 

(57) Abstract:

Use: in organic synthesis, to obtain pentaerythritol - intermediate production of paints and varnishes, plasticizers. The inventive product is pentaerythritol, the output 90 of 91.7%, so pl. 261 - 262oC. a Solution of pentaerythritol before the concentration process monoalkylphenols ether of polyethylene glycol, f-crystals, CnH2n+1C6H4O (C2H4O)mH, where m-6, n=8-10, taken in the amount of 110-3- 510-3% by weight of the solution. table 1.

The invention relates to the field of production of polyhydric alcohols, in particular pentaerythritol (PE), is widely used in the manufacture of paints, plasticizers and special purposes.

A method of obtaining PE [1] consisting in the fact that the crystallization of a saturated solution of PE are under stirring with gradual cooling to 35aboutC for 15-20 h

The disadvantages of this method consists in obtaining crystalline product (more than 40% of the product with the size of the crystals is less than 0.125 mm), which degrades the quality of the finished PE and products based on it and neschetov, burn, resulting resins dark color on the basis of which it is impossible to obtain coating materials and light colours, the desired shades.

The known method [2] more coarse PE, which is that for the destruction of the by-products of the condensation solution is treated with hydrogen peroxide in the ratio of 3-15 wt.h. peroxide per 100 wt.h. contained non-volatile organic substances in the solution.

The disadvantages of the method are significant concentrations of hydrogen peroxide, used for processing, its scarcity and high value. In addition, hydrogen peroxide is a very dangerous reagent from the point of view of ensuring the safety of workers.

Closest to the invention to the technical essence and the achieved result is a method [3] which crystalline PE receive (no more than 15% of the product with the crystal sizes less than 0.1 mm) by the condensation of acetaldehyde with formaldehyde using as catalyst, calcium hydroxide, by evaporation at a temperature not exceeding 80aboutWith up to a density of one stripped off solution 1,20-1,30 g/cm3with subsequent crystallization, dissolution with awho when receiving PE using as catalyst calcium hydroxide in the full actuation of formaldehyde along with the main reaction is the formation of a colored resinous products of sugary substances. The resulting by-products in - lead to obtaining small crystals of PE,which are poorly filtered, and the surface of the crystals poorly laundered by-products. In addition, in the process of evaporation is overgrowing and clogging of the tube bundles of the boiler evaporator due to deposits of mineral salts, mainly calcium sulphate, calcium formate and other contained in parivena solution. As a result, significantly reduces the heat transfer, and hence the performance of the evaporator, dramatically increases the steam consumption, longer process time. Evaporation occurs up to 18 hours as a result of this quality PE granulometric composition and the melting temperature.

The purpose of the invention is to provide such a method which would allow to eliminate the mentioned disadvantages, namely to increase the performance and manufacturability of the process and improve the quality of the finished product with uniform crystals of PE.

This goal is achieved by the fact that unlike the prototype of the proposed method using monoalkylphenols ether of polyethylene glycol of General formula

CnH2n+1C6H4

The essence of the method consists in the following. Carry out the condensation of acetaldehyde with formaldehyde in the presence of calcium hydroxide. After completion of the condensation reaction solution is treated with sulfuric acid separated gypsum is filtered off and the solution is added 110-35 10-3wt. Surfactants. After this, the solution evaporated under vacuum (-0,08 MPa) at a temperature of 70-75aboutWith up to a density of 1.24-1.28 g/cm3. Then one stripped off mass crystallized for 4 h to a temperature of 25-30aboutWith, separated from the mother liquor and subjected to recrystallization with activated carbon at 102-105aboutC for 1 h After recrystallization coal is separated and recrystallized mass is cooled to 30aboutWith and produce ready-PE. Get uniform large crystals of PE with high melting temperature. An unexpected effect and the solution PE, consequently, the increase in performance evaporator.

P R I m e R 1. The original solution of PE obtained by the condensation of acetaldehyde with formaldehyde using as catalyst calcium hydroxide in a molar ratio of 1:5:0,6, neutralized with sulfuric acid and separating the precipitated gypsum. The filtered solution contains 7.6% of PE, 0.14% of the free aldehydes, 0.25% sulfate and formate calcium and 2.5% formic acid. To 4 l of the resulting solution at 40aboutTo add 0,045 g (110-3% ) monoalkylphenols ether of polyethylene glycol, mixed and evaporated at a temperature of 70-75aboutWith under vacuum (-0,08 MPa) to a density of 1.24 g/cm3within 4 hours one stripped off the solution crystallized 4 h under stirring until 25aboutC. When 25aboutWith a suction filter to separate PE from the mother liquor by washing the crystals with water in the ratio of 1:0.8 to on draught. Obtain 290 g of crystals of PE and 400 ml of stock solution containing 4.0% of PE. Received PE recrystallized with activated carbon in a reactor with a reflux condenser load 250 g PE. 2 g of activated charcoal and 300 ml of water. The mass is heated to 105aboutWith and incubated for 1 h then the coal is separated in a heated which emit finished PE number 225, The output from stage condensing 90% of the Obtained crystals are dried and analyzed.

The product has the following characteristics:

The fraction of crystals with a diameter of 0.63 mm respectively 63%

The fraction of crystals with a diameter of 0.40 mm 37% melting point 262aboutWITH

P R I m m e R 2. To 4 l of the source of the condensation solution similar to example 1, at 40aboutWith added under stirring 0.125 g (3 10-3%) monoalkylphenols ether of polyethylene glycol and evaporated at a temperature of 70-75aboutWith under vacuum (-0,08 MPA) to a density of 1.26 g/cm3over 4.5 hours one stripped off the solution crystallized 4 h under stirring until 25aboutC. When 25aboutWith a suction filter to separate PE from the mother liquor, washing the crystals with water in the ratio of 1:0.8 to on draught. Get 293 g of crystals of PE and 390 ml of stock solution containing 3.8% PE. 250 g of the obtained crystals PE is subjected to recrystallization with activated carbon at 105aboutC for 1 h analogously to example 1. After recrystallization coal is separated and recrystallized mass is then cooled with constant stirring for 4 h 30aboutWith and produce finished PE number 227,5 g, which corresponds to 91% of the stage of condensation. The obtained crystals are dried and analizirate melting 262aboutC.

P R I m e R 3. To 4 l of the source of the condensation solution similar to example 1, at 45aboutWith added under stirring 0.21 g (510-3wt.) monoalkylphenols ether of polyethylene glycol and evaporated at a temperature of 70-75aboutWith under vacuum (-0,08 MPA) to a density of 1.28 g/cm3within 5 hours one stripped off the solution crystallized 4 h under stirring until 25aboutC. When 25aboutWith a suction filter to separate PE from the mother liquor, washing the crystals with water in the ratio of 1: 0.8 to on draught. Get 300 g of crystals of pentaerythritol and 375 ml of stock solution containing 3,74% PE. 250 g of the obtained crystals PE is subjected to recrystallization with activated carbon at 105aboutC for 1 h analogously to example 1. After recrystallization coal is separated and recrystallized mass is then cooled with constant stirring for 4 h 30aboutWith and produce finished PE number 230 g, which corresponds to a yield of 91.7% from the stage of condensation. The crystals are dried and analysed. Get: fraction of crystals with a diameter of 0.63 mm respectively 61%

the fraction of crystals with a diameter of 0.4 mm 39% melting point 261aboutC.

P R I m e R 4 (comparative). 4 l the source of the condensation solution, analogichnogo condensation of the surfactant solution. The duration of the evaporation until the specified density is 7.5 hours one stripped off the solution crystallized 4 h under stirring until 25aboutAnd on a suction filter to separate PE from the mother liquor by washing the crystals with water in the ratio 1: 1 by sediments. Get 275 g of crystals of PE and 460 ml of stock solution with the content of PE of 7.3% 250 g of the obtained crystals PE is subjected to recrystallization with activated carbon at 105aboutC for 1 h analogously to example 1. After recrystallization coal is separated and recrystallized mass with constant stirring is cooled within 4 hours to 30aboutWith and allocate 203 g of crystals of PE, which corresponds to a yield of 81% of the Crystals are dried and analyzed.

Get:

the fraction of crystals with a diameter of 0,63 mm 16,4%

the fraction of crystals with a diameter of 0.40 mm to 31.5%

the fraction of crystals with a diameter of 0.25 mm 21,0%

the fraction of crystals with a diameter of 0.125 mm 21,5%

the fraction of crystals with a diameter 0,100 mm 1,5%

the fraction of crystals with a diameter of less than 0.1 mm 8,1% melting point 251aboutC.

The table shows the characteristics of the methods of obtaining PE.

The table shows that the proposed method allows to intensify the process of evaporation of solutions of PE kolichestvo waste per unit of finished product.

The METHOD of producing PENTAERYTHRITOL condensation of acetaldehyde with formaldehyde in the presence of a catalyst is calcium hydroxide, followed by neutralization of the sulfuric acid, the separation of gypsum, the concentration of the solution, crystallization, separation of crystals of the target product and recrystallization from water with the addition of activated carbon, characterized in that before concentrating the solution process monoalkylphenols ether of polyethylene glycol of General formula

CnH2n+1C6H4O (C2H4O)mH,

where n = 8 to 10;

m = 6,

taken in quantities of 1 to 10-3- 5 10-3by weight of the solution.

 

Same patents:

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.

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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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