Method of processing commercial pentaerythritol-formiate mother solution

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

 

The present invention relates to technology of organic synthesis, namely the method of production of pentaerythritol and sodium formate, and can be used in chemical, paint and other industries.

A known method of separation of pentaerythritol, dipentaerythritol and polypentaerythritols from the mother solution obtained after separation of pentaerythritol (RF patent No. 857102, C07C 31/24, 1981). The known method consists in heating the starting solution to 90-107°C and cooling the mixture obtained in two steps to 15-45°C, separated by filtration of precipitated in the sediment of polypentaerythritols and dipentaerythritol with further evaporation of the residual solution and crystallization of pentaerythritol.

The disadvantage of this method is the increase of viscosity upon cooling the concentrated mixture, which reduces the efficiency of the separation of pentaerythritol and sodium formate in the mother solution.

There is a method of processing a mixture of uterine PENTAERYTHRITE-formiate solutions (RF patent 2304012, B01D 1/26, D01D 9/02, C07C 31/24, C07C 53/06, 2007), adopted as closest as closest solve the technical problem consisting in concentrating the solution until saturation state for pentaerythritol by evaporation in a film flow of the solution and crystallization of pentaerythritol carried out in two stages with a reduction is receiving temperature at the second stage and the subsequent separation of the solid and liquid phases.

The lack closest analogue is that while improving the quality and extent of extraction of technical pentaerythritol mother liquor known method is technologically complex.

The technical object of the present invention is to improve the efficiency of allocation of pentaerythritol and sodium formate technical pentaerythritol-formatage the mother liquor, while ensuring quality of the products.

The technical result consists in providing separate crystallization of pentaerythritol and sodium formate.

The technical result is achieved in that in the method of processing technical pentaerythritol-formatage the mother liquor, which consists in the selection of pentaerythritol, and separating the liquid phase, according to the invention, the mother liquor is diluted with water to a content of sodium formiate 30-32%, the resulting solution was heated to a temperature of at least 60°C, stirred it at this temperature with a speed of 900-1000 rpm for at least 4 hours, the resulting suspension is filtered on a vacuum filter with deposition of pentaerythritol and separation of the filtrate containing the sodium formate. In addition, the besieged pentaerythritol diluted with water to a content of pentaerythritol in a mixture of 23-25%, heat it to a temperature of at least 80°C, filtered using activated the bathing coal, evaporated and dried the precipitate.

The technical result is ensured by the fact that the mother liquor is diluted with water to a concentration of predominant component to it - formate sodium 30-32%, which allows to facilitate the separation of pentaerythritol and sodium formate in the mother solution by eliminating the possibility of their joint crystallization and formation of a thick syrupy mixtures of sugars and other organic impurities, derived pentaerythritol, complicating the selection of pentaerythritol and sodium formate and reduce the quality of the finished products. Experiments have shown that the greatest amount of solid phase is highlighted in the process of separating the mother liquor diluted with water up to 30-32% sodium formate.

It is known that the process of crystallization at a temperature of at least 60°C leads to a decrease of viscosity solutions and promotes the formation of larger crystals. When heating a crystalline precipitate of pentaerythritol in contact with mother liquor is a process of maturation of sediment, which consists in the dissolution of small crystals and ordering the growth of large crystals. The result is a more pure crystalline precipitate of crystals of a more regular shape. The combination of heating the mother liquor with stirring facilitates the diffusion of Christ is lisauskas component to the surface of a growing crystal and reduces the viscosity of the mother liquor.

By practice it is found that from the diluted mother liquor containing sodium formate 30-32%, heated to a temperature of at least 60°C and with constant stirring of the solution with the speed of 900-1100 rpm for 4 hours is provided by the selection in the solid phase, more than half contained in the mother solution of pentaerythritol with that obtained after filtration on a vacuum filter liquid phase containing sodium formate, is returned to the line for sodium formate.

The proposed method is as follows.

Technical pentaerythritol-formity mother solution has a density of ρ80=1,36-1,40 g/cm3and contains a significant amount of valuable components: sodium formate is 35-40% and monopentaerythritol - 18-26%and 2-3% of organic impurities (the products of the side reactions) and the rest is water.

Technical the mother liquor is diluted with water to a concentration of 30-32% sodium formate. Dilution technical stock solution by the most prevalent component of the sodium formate carried out in order to avoid its immediate crystallization at lower temperatures, as part of the original technical stock solution is in joint crystallization of pentaerythritol and sodium formate.

Diluted technical mother liquor, for example, which indicate the crystallization by constant stirring speed 900-1100 rpm at 60°C for 4 hours. After 4 hours of crystallization obtained pentaerythritol-formatua the suspension is sent to the vacuum filter to separate the liquid and solid phase. During the separation of the filter is deposited solid phase - pentaerythritol, containing in its composition: monopentaerythritol - 61-84 wt.%; formate sodium - 9-25%; impurities 3-12%, including dipentaerythritol, formally mono - and dipentaerythritol various buildings, as well as sugary substances that are formed due to the condensation of formaldehyde in an alkaline environment and are a mixture of various sugars.

The obtained pentaerythritol may be an indicator of quality "chroma" - 700-750 units on platinum cobalt scale, indicating a high content of impurities. To reduce the parameter "color" besieged pentaerythritol diluted with water content in the mixture of pentaerythritol - 23-25% at a temperature of 80°C and pass the resulting solution through a column equipped with activated carbon under the influence of gravity. Missed the solution evaporated with further drying the obtained precipitate.

The filtrate containing the sodium formate obtained after stage filtration with density ρ50=1,2880-1,3075 g/cm3including - monopentaerythritol - 11-13,5%, sodium formate - 32-37% and impurities 8-13,5%, containing dipentaerythritol, formally mono - and dipentaerythritol R is lichnogo structure, sugary substances, return to the line for sodium formate, with the aim of increasing the yield of sodium formate as the finished product. This is contained in the liquid phase pentaerythritol remain in the process stream and released during the following cycles.

Example.

For experiments on the separation of the mother liquor on a solid and liquid phase samples were taken in 250 ml technical pentaerythritol-formatage the mother liquor. The samples were diluted with process water to 30-32% content of sodium formiate. Process water is water used in JSC "Metafrax" in the production of pentaerythritol, corresponding in composition to the company's standard one HUNDRED 23-2007. The use of process water in the proposed method is cost-efficient.

The solution was stirred for 4 hours at 60°C and at a speed mixer of 1000 rpm Then the solution with the precipitate was filtered under vacuum using a Buchner funnel. The crystals of the solid phase obtained quite large, so the filtering under vacuum passed without difficulty. The precipitate was removed from the filter and dried. The filtrate and dry sediment was weighed, and determined the concentration of monopentaerythritol and sodium formate. Conducted an analysis of the solid phase on the content of sugars, chromatographic analysis of the content of the derivative of pentaerythritol, determine what their colour by the platinum-cobalt scale.

The results of experiments on the separation of technical pentaerythritol-formatage stock solution into solid and liquid phases of the proposed method: the composition of the solid and liquid phases and the percentage of monopentaerythritol and sodium formate depending on the content of sodium formiate in the diluted mother solution is given in the table.

Table
The content of HCOONa in the mother solution after rubbable
tion, %
Characteristics of products the separation of the mother liquor
Solid phaseThe liquid phase
HCOONa, %The IPE, %Σ
use
this
Color
an activity unit
The density ρ50,g/cm3HCOONa, %The IPE, %Σ impurities
31,9316,4974,00of 3.077501,302236,7111,99 10,63
31,0424,8361,545,61700at 1.324135,3312,63of 10.25
30,0014,4070,2611,947501,307436,2412,5813,38
30,0012,8878,384,287001,299932,9912,2510,85
30,009,9883,68was 2.767001,288133,0012,71are 11.62
Note: HCOONa - formate sodium; IPE - monopentaerythritol.

Experiments allow us to establish that the chosen conditions the content of the diluted mother solution of sodium formiate - 30-32%, heating the diluted mother liquor to a temperature of at least 60°C, the speed of mixing is 900-1000 rpm and mixing time is not less than 4 hours provide separate crystallization of pentaerythritol and sodium formate and highlight in the solid phase until half is contained in the original sample of pentaerythritol.

At present JSC "Metafrax" annual production of technical stock solution 38188 tons of the proposed method additionally allows you to allocate up to 3800 tons of pentaerythritol.

Thus, the proposed method allows for the separate crystallization of pentaerythritol and sodium formate, and thus improve the manufacturability processing PENTAERYTHRITE-formatage the mother liquor with the release of pentaerythritol and sodium formate.

1. A method of processing technical pentaerythritol-formatage the mother liquor, which consists in the selection of pentaerythritol, and separating the liquid phase, characterized in that the mother liquor is diluted with water to a content of sodium formiate 30-32%, the resulting solution was heated to a temperature of at least 60°C, stirred it at this temperature with a speed of 900-1100 rpm not less than 4 hours, the resulting suspension is filtered on a vacuum filter with deposition of pentaerythritol and a separation filter is the one containing sodium formate, which secrete sodium formate.

2. The method according to claim 1, characterized in that the besieged pentaerythritol add water until the content of pentaerythritol in a mixture of 23-25%, heat it to a temperature of at least 80°C, filtered with activated charcoal, evaporated and dried the precipitate.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing a solid sodium diformate composition, having forming acid content of at least 35% of the total weight of the sodium diformate composition, in which aqueous solution (E) is prepared at high temperature, said solution containing sodium formate and formic acid in molar ratio HCOOH:HCOONa higher than 1.5:1, and having molar ratio HCOOH:H2O of at least 1.1:1, said aqueous solution (E) is crystallised to obtain a solid phase and a mother solution, and the solid phase is separated from the mother solution, where (i) the mother solution is completely or partially fed into a distillation apparatus; (ii) the mother solution in the distillation apparatus is mixed with a sodium-containing base to obtain a mixture (B) which contains sodium formate and formic acid; (iii) the mixture (B) obtained at step (ii) is mixed with formic acid to obtain aqueous solution (E); or the mixture (B) obtained at step (ii) is removed from the distillation apparatus and taken for crystallisation, or, at the crystallisation step, mixed with formic acid to obtain an aqueous solution; and (iv) excess water is primarily removed by tapping from the distillation apparatus; the invention also relates to use of the solid sodium formate composition obtained using the disclosed method as an animal feed additive, particularly feed for non-ruminants, especially pigs and/or birds.

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29 cl, 3 dwg, 1 tbl, 4 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.

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2 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of preparing a sodium formate-containing composition with formic acid content of not less than 35 % of the total weight of the said composition, in which a) a stream of formic acid with formic acid content of not less than 74 wt % is provided; b) a stream of formic acid from step a) together with sodium formate-containing streams from step f) and step h) are taken to the crystallisation step where an aqueous solution is obtained at high temperature, where the said solution has molar ratio HCOOH:Na[HCOO] greater than 1.5:1 and molar ratio HCOOH: H2O equal to at least 1.1:1; c) at the crystallisation step the aqueous solution from step b) is crystallised to obtain a stream which contains a solid phase and a mother solution; d) the stream obtained from step c) is taken to a separation step on which the solid phase is separated from the mother solution to obtain a stream which contains sodium diformate and a stream which contains a mother solution; e) the stream which contains the mother solution from step d) is divided into two parts; f) one part of the stream from step c) in form of a portion (A) is returned to step b); g) the other part of the stream from step e) in form of a portion (B) together with the stream, including a base, which contains sodium is taken to a neutralisation step to obtain a mixture which contains sodium formate, and where portions of the mother solution (A) and (B) complement each other to 100 wt %, and the weight ratio of portion (A) of the mother solution to portion (B) lies between 20:1 and 1:10; and b) the sodium formate-containing mixture from step g) and optionally from step h), if necessary after its withdrawal, is taken to the concentration step in form of a stream where a portion of water contained in that stream is released, where after separation of the portion of water a stream which contains sodium formate is obtained, which is directly returned to step b) or crystallised at the second crystallisation and separation step, and the obtained liquid phase is taken to the concentration step h) in form of a stream, and the solid phase is taken in form of a stream to step b). The obtained product can be used in industrial production, especially at relatively low temperatures.

EFFECT: improved method of preparing a sodium formate-containing composition with formic acid content of not less than 35% of the total weight of the said composition; obtained product has antibacterial activity and is used in preservation for example, as well as for acidification of animal and plant material.

16 cl, 5 dwg, 7 ex, 8 tbl

FIELD: chemistry.

SUBSTANCE: method of separating multi-atom alcohols, for instance, neopentylglycol and sodium formiate, includes evaporation and cooling of reaction mixture, addition of organic solvent, crystallisation of sodium formiate, separation of sodium formiate from saturated solution of multi-atom alcohol, for instance, by filtration, and crystallisation of multi-atom alcohol. Reaction mixture is evaporated until two liquid layers are formed, which are separated into light phase - water-multi-atom alcohol and heavy phase -water-salt, separated water-salt fraction of solution is cooled until sodium formiate contained in it in form of cryslallohydrate is crystallised, sodium formiate crystals are separated, and remaining mother-solution is returned to process head, to evaporation stage, then separated light phase - water-multi-atom alcohol is additionally evaporated until 70% of contained in it sodium formiate is crystallised, then cooled to 25-30°C and subjected to processing with organic solvent from line of single-atom saturated alcohols, for instance, methane, for removal of remaining admixtures, with further crystallisation of multi-atom alcohol from remaining mother-solution.

EFFECT: reduction of amount of used organic solvent, elimination of high-temperature stage of extraction, preservation of yield of pure target products.

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FIELD: chemistry.

SUBSTANCE: preparation of liquid flow I, containing formic acid, and liquid flow II, containing alkali metal formate, is carried out; liquid flows I and II are supplied to rectification column in such way that for liquid flow II place for feeding into rectifying column is chosen higher than place of feeding liquid flow I, or the same place as for liquid flow I, liquid flows I and II are mixed in rectification column, removing water from upper part of rectification column, and lower flow, containing formic acid formate is removed from rectification column, lower flow being separated in form of melt, which contains less than 0.5 wt % of water.

EFFECT: improved method of production of formic acid formates.

10 cl, 4 ex

FIELD: chemical industry; methods of production of the manganese salts with the organic acids.

SUBSTANCE: the invention is pertaining to production of the manganese salts with the organic acids in particular, to the salt of the divalent manganese and formic acid. The method is exercised by interaction of manganese, its oxides in the state of the highest valence with the formic acid solution in the organic solvent in the presence of iodine as the stimulating additive. The production process is conducted in the bead grinder of the vertical type having the revertive cooler-condenser, the high-speed paddle stirrer and the glass beads of in the capacity of the grinding agent loaded in the mass ratio to the loading of the liquid phase as (1÷2): 1. The liquid phase consists of the formic acid solution in the organic solvent. The concentration of the acid is taken within the range of 3.5÷10.8 mole/kg. In the loaded liquid phase they dissolve the stimulating additive of iodine in the amount of 0.025-0.100 mole/kg of the liquid phase. The ratio of the masses of the liquid phase and the total of the metallic manganese and the manganese oxide are as(4.9÷11):1. The molar ratio of the metal and the oxide in the loading is as (1.8÷2.,2):1. The metal and the oxide are loaded the last. It is preferable in the capacity of the dissolvent to use the butyl alcohol, ethyl acetate, ethylene glycol, 1.4-dioxane, dimethyl formamide. The production process is started and conducted at the indoor temperature up to practically complete(consumption of the whole loaded manganese oxide. Then the stirring is stopped, the suspension of the salt is separated from the beads and the nonreacted manganese and after that conduct filtration. The filtrate and the nonreacted manganese are returned into the repeated production process, and the filtered out settling of the manganese salt is exposed to purification by recrystallization. The technical result of the invention is - simplification of the method at usage of accessible reactants.

EFFECT: the invention ensures simplification of the method at usage of accessible reactants.

16 ex, 2 tbl

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: inorganic synthesis.

SUBSTANCE: invention relates to preparation of salts of transition metals with organic acids, in particular to formic acid ferric salt. Method is accomplished via oxidation of ferrous formate with hydrogen peroxide in presence of formic acid and in absence of any dorm of iron as reducer in order to prevent reduction of ferric salt into original ferrous salt. As reducer, ferrous formate is used preliminarily recrystallized and dried or filtered off from reaction mixture suspension. Process is carried out in upright bead mill in two steps. In the first step, ferrous formate powder or precipitate is combined, stepwise or in one go, with 85% formic acid or mixture of filtrate with wash water formed during isolation of desired product to form pasty slurry ensuring stable functioning of bead mill. Second-step operation is effected in bead mill functioning mode involving forced cooling through side surfaces of reactor and continuous introduction of 12.5-25% hydrogen peroxide solution at a rate of 3.25-4.24 g H2O2 per 1 kg starting charge until degree of Fe(II) salt conversion achieves 85-90%. Supply velocity is then lowered until complete conversion is reached. Resulting product slurry is separated from beads and filtered. Filter cake is washed with 85% formic acid and recrystallized in saturated ferric formate solution containing 20-30% of formic acid. Wash liquid is combined with filtrate and used in the first step as described above.

EFFECT: increased yield of target product and simplified its isolation step.

1 tbl, 8 ex

FIELD: inorganic synthesis.

SUBSTANCE: invention relates to preparation of salts of transition metals with organic acids, in particular to formic acid ferric salt. Method is accomplished in bead mill provided with mechanical blade-type stirrer in aqueous formic acid solution (5-10 mole/kg). Iron is used in the form of steel sidewall across the height of reactor and also as particles of reduced iron stirred with stirrer together with glass beads, and/or as broken steel cuttings, and/or yet as split cast iron in any weight proportions. Method is accomplished by continuously introducing 10-20% hydrogen peroxide solution at a rate of 0.015-0,030 mole peroxide/min per 1 kg liquid phase (salt slurry) in presence of stimulating additive, in particular iodine, bromine, alkali metal or ferrous iodides or bromides in amounts (on conversion to halogens) 0.1-0.15 vole per 1 kg reaction mixture. When 1,2-1,5 mole/kg of ferrous salt is accumulated in reaction mixture, stirring and addition of hydrogen peroxide solution are stopped, product slurry is separated from unreacted iron and/or its alloys as well as from glass beads and filtered. Filtrate is recycled into process and precipitate is recrystallized from saturated iron formate solution of aqueous formic acid solution (1-2 mole/kg).

EFFECT: simplified finished product isolation stage, reduced total process time, and reduced power consumption.

1 tbl, 11 ex

FIELD: chemical industry; methods of production of the salts of iron and the organic acids.

SUBSTANCE: the invention is pertaining to the field of chemical industry, in particular, to the method of production of the salts of iron and the organic acids, in particular, to production of the salt of the ferrous iron and the formic acid. The method is realized by the direct interaction of the acid with the iron, its alloys and the ferric oxides. The crumber with the beads and the backflow condenser is loaded with the organic solvent, the formic acid and the water in the mass ratio of 100:(85÷100): (15÷0). As the organic solvent they use ethylcellosolve, butyl acetate, butyl and amyl alcohols, ethylene glycol. The mass ratio of the beads and the liquid phase is 1:1. Ferric oxideFe2O3 orFe3O4 and the iodine are loaded in the amount of 0.40-0.56 or 0/21-0.42 and 0.03-0.1 mole/kg of the liquid phase accordingly. The iron is introduced in the form of the steel shell along the whole height of the reactor and additionally in form of the reduced iron, the fractions of the broken cast iron with dimensions of up to 5 mm and the steel chips in any ratio among themselves at total amount of 20 % from the mass of the liquid phase. The process is conducted at the temperature of 35-55°С practically till the complete consumption of the ferric oxide. The gained suspension is separated from the beads and the metal particles of the greater dimensions and subjected to centrifuging or sedimentation. The clarified liquid phase is returned to the repeated process, and the solid phase is dissolved at stirring action and warming up to 85-95°С in the water solution of the formic acid saturated by the ferric formiate (II) up to 1-2 mole/kg. The present solid impurities are removed at the hot filtration process and the filtrate is cooled and the salt crystals are separated. The technical result of the invention is simplification of the technology of the production process with utilization of the accessible raw.

EFFECT: the invention ensures simplification of the technology of the production process with utilization of the accessible raw.

3 cl, 17 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

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

FIELD: metallurgy.

SUBSTANCE: for execution of zone melting the unit on the basis of roller or belt crystalliser includes reservoir 2 with molten metal 1, rotary cooled roll 3 or moving closed belt, one or more heaters 6 located between the section on which roll 3 or belt contacts molten metal 1 and device 8 for removing crystalline layer and providing formation of one or more local melting zones lying on the generatrix of roll 3. Heaters 6 have the possibility of periodic stop of heating of crystalline layer for formation of alternating sections of crystalline layer with various content of impurity: enriched with impurity and purified. For final separation the crystalliser also includes device 9 for selective removal of crystalline layer from the specified sections of roll 3 or belt in periodic mode.

EFFECT: invention allows carrying out continuous process of cleaning or separation of substances with directed crystallisation processes on cooled surface and zone melting, which are combined in one and the same unit.

2 cl, 1 dwg

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