Method of producing pentaerythritol

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 40±2°C 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 40-45°C. Further, acetaldehyde cooled to -10±0.1°C 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 60°C. 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

 

The invention relates to the technology of polyhydric alcohols, can be used to obtain the pentaerythritol used in the manufacture of varnishes, plastics, explosives.

A known method of producing pentaerythritol in A.S. No. 300018, SS 31/24, 1971, by the condensation of formaldehyde with acetaldehyde in the presence of a hydroxide of an alkaline or alkaline earth metals when heated with subsequent isolation of the target product known techniques. The disadvantage is the small number of pentaerythritol output, low quality product.

A known method of producing pentaerythritol according to the patent of Russian Federation №2053215, SS 31/24, 1996. The method includes the interaction of acetaldehyde with formaldehyde in the presence of sodium hydroxide, distillation and evaporation of the reaction mixture, crystallization, filtration, washing and drying of pentaerythritol. From the dried product to produce lumps, crushed them, and conduct additional heat treatment by the heat carrier. The disadvantage is the duration of distillation and crystallization, affecting the quality of the product.

As the closest analogue of the claimed invention selected technical solution for RF patent for the invention №2208009, SS 31/24, 2003. The method of producing pentaerythritol with a basic substance content of more than 98 mA is.% and pentaerythritol, enriched with dipentaerythritol in the amount of 5-20 wt.%, is the condensation of acetaldehyde with formaldehyde in an aqueous alkaline medium, followed by neutralization of the reaction mixture, the desorption of excess formaldehyde, evaporation, vacuum crystallization, filtration, washing and drying emitting pentaerythritol. At the next stage, the filtrate of the suspension of technical pentaerythritol and the filtrate from the stage of recrystallization unite, evaporated, and subjected to vacuum crystallization, filtered, the residue is recrystallized in hot water, filtered and dried to obtain pentaerythritol. The disadvantage is the complexity and duration of the process of obtaining pentaerythritol high quality, long time condensation of acetaldehyde with formaldehyde, the complexity of the technological process related to the fact that the use of an aqueous solution of formaldehyde required to maintain a certain temperature during storage and loaded into the reaction. In addition, the shelf life of aqueous solution of formaldehyde, formalin, very low. So the enrollment shall take place immediately before carrying out the condensation of formaldehyde with acetaldehyde, which significantly lengthens and complicates the process.

The technical task of the invention is to increase the technologist is knosti process of obtaining pentaerythritol, while ensuring product quality.

The technical result of the claimed invention is to improve the technological process of obtaining pentaerythritol.

The technical result is achieved due to the fact that in the method of producing pentaerythritol, which consists in the condensation of formaldehyde with acetaldehyde in the presence of caustic soda, crystallization, filtration and drying of pentaerythritol, according to the invention, as the source of formaldehyde is used paraformaldehyde in the form of granules, in which water is added at a temperature of 40±2°C and stirred for 4.5-5.5 minutes, then hold preliminary dissolving paraformaldehyde in alkaline sodium hydroxide solution taken in the amount of 30% of the total load of caustic soda, for 15-16,5 minutes at a temperature of from 40 to 45°C later in the cooling conditions add acetaldehyde, cooled to -10±0.1°C and the residual quantity of caustic soda, gradually increasing the temperature of the condensation solution to 60°C is maintained for 15 minutes, add in the condensation formic acid to achieve a pH of 6.5.

The technical result is ensured by the fact that as the source of formaldehyde condensation using paraformaldehyde, which is in a solid state in the form of granules. This allows the use of paraformaldehyde produced previously stored in the warehouse or transportation is truely, in contrast to the use of an aqueous solution of formaldehyde is formalin. The use of formalin in this process is only possible if the temperature is not less than 60°C, which significantly complicates the process. At a lower temperature storage and use is the reaction of polymerization. The use of paraformaldehyde pellets facilitates its storage, delivery to the reactor and loading. Pre-dissolving paraformaldehyde in water, and then in alkaline sodium hydroxide solution is carried out with the aim of converting paraformaldehyde formaldehyde required for condensation with acetaldehyde. When this occurs pre-gap polymer chains, allowing to reduce the time of the condensation process. Optimal conditions of preliminary dissolution was determined experimentally. The data given in the table, which shows that when the amount of caustic soda 30%from the total load at a temperature of 40-45°C and time of the pre-dissolution within 15 minutes, get the largest number of pentaerythritol - 89,69%, containing monopentaerythritol(IPE) - 86,79%, dipentaerythritol(DEP) is 1.16%, usinternational(BPAP) - 1.74 percent.

Pre-dissolving paraformaldehyde in alkali at t=40-45°C
Quantity of NaOH in % of total load101520304050
Time tentatively. dissolution, min57,510152025
The output of the IPE, %86,4585,1385,5586,7984,4485,97
The output of the DEP, %1,061,140,931,160,730,95
Output BPAF, %1,451,401,511,741,491,09
∑ output %88,9687,68 87,9889,6986,6688,00

Cooling of acetaldehyde to -10±0.1°C before the reaction and loaded into a reaction chamber under conditions of cooling also reduces the total time of synthesis, because there is an acceleration of the process of crystallization of pentaerythritol. Add in the condensation of the acid solution to pH b,5 it is possible under these conditions the condensation does not exceed the permissible value of sugar, high concentrations of which depend on the reduction in the quality of the product. In particular, affects its color. The use of paraformaldehyde pellets are more technologically sophisticated than the use in the form of loose powder, as granules are non-hygroscopic, does not stick together during storage, allow for a more uniform loading before the beginning of the reaction.

The process of obtaining pentaerythritol using as feedstock of paraformaldehyde is carried out in three stages. The first stage involves the preparation of raw materials. For carrying out the synthesis of pentaerythritol use the following components: aldehyde uxury technical with mass fractions of the basic substance - 99,79%, caustic soda technical with mass fractions of the basic substance - 48,63%paraformaldehyde "Granuform 91" with mass fractions of the basic substance - 91,00%, formic acid with the obsession of the basic substance - of 86.00%, distilled water. Before downloading acetaldehyde cooled to a temperature of -10±0,01°C. the Second stage is pre-dissolving paraformaldehyde in alkaline solution. The required amount of water and parafomaldehyde loaded into a mixing device, carry out the dissolving paraformaldehyde at a temperature of 40°C for 5 minutes with constant stirring speed of 300 rpm. Next, add the calculated amount of caustic soda in amount of 30% of the total load. Spend the third stage, involving the condensation of aldehydes. After pre-dissolving paraformaldehyde in the reaction mixture gradually add the calculated amount of acetaldehyde. Synthesis of pentaerythritol is carried out at the following molar ratio of the components:

Acetaldehyde: Paraformaldehyde: Alkaline: Water=1:8:1,2:72. During the dosing of all components increase the temperature to 60°Scintas pentaerythritol spend within 44-47 minutes, then for 15 minutes, spend it wisely. After soaking in the condensation solution add formic acid to achieve a pH of 6.5. The output of pentaerythritol is 86,79% of theoretical, the sugar content in it is 0.56%. The obtained pentaerythritol is filtered and dried.

Thus, the claimed izaberete what I can improve the manufacturability of the process of obtaining pentaerythritol due to the advantages of using a feedstock of granulated pentaerythritol and reduce the time of condensation.

The method of producing pentaerythritol, which consists in the condensation of formaldehyde with acetaldehyde in the presence of caustic soda, crystallization, filtration and drying of pentaerythritol, wherein the source of formaldehyde is used paraformaldehyde in the form of granules, in which water is added at a temperature of (40±2)°C and stirred for 4.5 to 5.5 min, then hold preliminary dissolving paraformaldehyde in alkaline sodium hydroxide solution taken in the amount of 30% of the total load of caustic soda, for 15-16,5 minutes at a temperature of from 40 to 45°C, then cooling conditions add acetaldehyde, cooled to (-10±0,1)°C and the residual quantity of caustic soda, gradually increasing the temperature of the condensation solution to 60°C is maintained for 15 minutes, add in the condensation formic acid to achieve a pH of 6.5.



 

Same patents:

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: 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 60°C 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: 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 15-25°C, 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: 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 10-80°C 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: 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

The invention relates to an improved process for the preparation of pentaerythritol with a basic substance content of more than 98 wt.% and pentaerythritol, enriched dipentaerythritol in the amount of 5-20 wt.%, used in paint and other industries

The invention relates to a method for the simultaneous receipt of pentaerythritol and sodium formate used in the chemical, leather and paint and other industries

The invention relates to a method for pentaerythritol by the interaction of acetaldehyde with an excess of formaldehyde in the presence of sodium hydroxide

The invention relates to the production of polyhydric alcohols, in particular pentaerythritol (PE), is widely used in the manufacture of paints and varnishes, plasticizers, and relates to a method of obtaining a PE in the presence of calcium hydroxide

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: 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 10-80°C 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

The invention relates to an improved process for the preparation of pentaerythritol with a basic substance content of more than 98 wt.% and pentaerythritol, enriched dipentaerythritol in the amount of 5-20 wt.%, used in paint and other industries

The invention relates to a method for pentaerythritol by the interaction of acetaldehyde with an excess of formaldehyde in the presence of sodium hydroxide

The invention relates to a method for producing a halogenated alcohol of the formula I, CF3-СХСl-CH(OH)-CH= C(CH3)2where X represents chlorine or bromine, which includes the interaction of the compounds of formula II CF3-CHXCl with 3-methylbut-2-EN-1-Alem in the presence of a strong base and in an inert solvent

The invention relates to the production of polyhydric alcohols, in particular pentaerythritol (PE), is widely used in the manufacture of paints and varnishes, plasticizers, and relates to a method of obtaining a PE in the presence of calcium hydroxide

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

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 10-80°C 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: 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 40±2°C 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 40-45°C. Further, acetaldehyde cooled to -10±0.1°C 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 60°C. 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

Up!