Method of processing technical pentaerythrite-formiate mother liquor

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

 



 

Same patents:

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: 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 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: 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 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: 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: 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: 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

FIELD: chemistry.

SUBSTANCE: invention relates to chemical industry. A method of separating fullerenes includes dissolving fullerenes in o-xylene, high-temperature treatment of the obtained solution at 70-90C for 60-120 minutes to obtain a C60 concentrate and a solution which is fed for low-temperature treatment at temperature of (-15) to (-25)C for 10-30 hours. Separation is carried out in multiple steps to obtain at each n step C60 and C70 concentrates with counterflow of the solutions and the solid phase from the high-temperature treatment. Several high-temperature treatment steps are carried out at each n step. At the first high-temperature treatment step of each n step, a solid extract of a fullerene mixture is fed and at the next steps, a solid phase from the previous high-temperature treatment step is fed. A solution from the first high-temperature treatment step is fed for low-temperature treatment to obtain a C70 concentrate and a solution which is fed to the last high-temperature treatment step. A solution from the next high-temperature treatment step is fed as a recycled solution to the previous step, and a solution from the second high-temperature treatment step is fed for mixing with the solid extract of the fullerene mixture of the next n>1 step. The C60 concentrate is the solid phase of the last high-temperature treatment step of each n step.

EFFECT: low material consumption and simple process.

2 cl, 2 dwg, 1 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: method includes crystallisation, further separation and drying of crystals with an application of vibration fluctuations in the range of fluctuation accelerations 20-70 m/s2 and amplitude 2-5 mm, with separation of crystalline substances from a liquid phase being carried out by the supply of the suspension to filtering partitions, installed with a clearance one under another in a descending order of the cell size and performing directed fluctuations at an angle from 30 to 60 to horizontal.

EFFECT: invention makes it possible to obtain monodisperse fractions of crystalline substances of a specified granulometric composition, which results in an improvement of quality of the target crystalline products and increases efficiency of processes of drying and filtration, to eliminate additional operations of grinding or crushing.

3 dwg, 3 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry. Sodium chloride is produced by first preparing a salt solution containing at least 150 g/l sodium chloride by dissolving a sodium chloride source in water. The obtained salt solution is subjected to eutectic crystallisation by freezing via direct cooling of said salt solution, which results in formation of ice, sodium chloride dihydrate and a mother solution. Further, the formed sodium chloride dihydrate is separated from the ice and optionally from the mother solution at eutectic point such that a stream rich in sodium chloride dihydrate is formed. Further, said stream rich in sodium chloride dihydrate is fed into a recrystalliser to form sodium chloride and a mother solution.

EFFECT: invention reduces power consumption during industrial production of pure sodium chloride.

16 cl, 1 dwg, 2 tbl, 2 ex

FIELD: process engineering.

SUBSTANCE: invention relates to chemistry. Proposed plant comprises crystallisation reservoir furnished with adipinic acid mixers, coolers and/or concentrators Note here that, at least, a part of the walls of said coolers and/or concentrators in contact with adipinic acid solution is made from material selected from austenitic stainless steels of AISI 310L-grade compliance with AISI (USA) nomenclature of European nomenclature XlCrNi25-21 (1.4335).

EFFECT: reduced "lining" effect and deterioration of plant surface

7 cl, 2 tbl

FIELD: process engineering.

SUBSTANCE: invention relates to filtration. Method of crystalline suspension filtration for extraction of crystals by continuous vacuum filtration comprises filtration, flushing and lifting-on of suspension bearing crystals and solvent to be carried out multiple times. It differs from known procedures in that crystals are flushed by flushing fluid overheated to, at least, vapor point.

EFFECT: rued out clogging.

5 cl, 3 dwg

FIELD: process engineering.

SUBSTANCE: invention relates to crystallising evaporator. Proposed evaporator consists of heated rotary case with inner perforated helical nozzle. Discharge branch pipe is arranged at case bottom. Heated rotary insert with outer perforated helical nozzle is arranged coaxially with case. Space between case and insert is filled with intermediate heat carrier. Intermediate heat carrier consists of separate elements. Axial rotation of said case and insert causes intensive circulation of intermediate hear carrier elements. Evaporated solution is fed into crystallising dish via spraying system on heated intermediate heat carrier. Aforesaid intensive circulation allows producing developed surface for solution evaporation in continuous cleaning of all surface of formed crystals.

EFFECT: higher efficiency of evaporation.

1 dwg

FIELD: chemistry.

SUBSTANCE: method of separating acrylic and benzoic acid contained in a gas mixture of products of partial oxidation into acrylic acid, during which acrylic and benzoic acid are first converted to a liquid phase from which, using a thermal separation technique, components with lower boiling point than benzoic and acrylic acid are then separated and acrylic acid is then separated from the remaining liquid phase by crystallisation. The method does not require energy consuming separation techniques. There is basically no fusion of benzoic acid into a crystal during crystallisation, which forms the basis of marked efficiency of the procedure according to the disclosed method.

EFFECT: less energy consuming separation technique.

22 cl, 1 ex, 1 tbl

FIELD: chemistry.

SUBSTANCE: method of separating potassium chloride and sodium chloride involves (a) obtaining a solution of said salts, which is heated to at least 50C, (b) removing water from the obtained solution via membrane distillation using a waterproof membrane and precipitation of sodium chloride, (c) separating the precipitated sodium chloride from the solution, (d) cooling the solution with precipitation of potassium chloride, (e) separating potassium chloride from the solution. The solution which remains after step (e) is heated through heat exchange with the solution fed to step (d) and recycled. In another version, the solution which remains after step (e) is mixed with water removed at step (b), heated and used at step (a).

EFFECT: invention enables to remove water completely from process streams, thus preventing its loss, and also enables extraction of potassium chloride.

12 cl, 3 dwg

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: 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

FIELD: radiochemical industry.

SUBSTANCE: proposed method includes crystallization of uranyl hexahydro-nitrate from solution by cooling it down. In the process uranyl nitrate solution is pre-evaporated to uranium concentration of 800-1300 g/l and to nitric acid concentration of 0.5-3.0 mole/l. Crystallization is conducted in concurrent flow of uranyl hexahydro-nitrate crystals formed in the process and mother solution while permanently stirring and cooling solution to 15-30 oC. Crystals are separated from mother solution and washed in concurrent flow at 15-30 oC in wash solution containing 250-300 g/l of uranium and 3.0-6.0 mole/l of nitric acid. Then crystals are taken out and dried. Device implementing this method has crystallization vat made in the form of externally cooled tube. In addition vertically disposed crystallization vat accommodates blade mixer. Uranyl nitrate solution feed union is disposed in top part of crystallization vat. Bottom part of the latter is placed coaxially with wash-over string and secured in hole of its lid provided with pipe union for joint outlet of mother solution and waste wash solution. Bottom part of wash-over string is joined at certain angle to auger-accommodating inclined tube. Top part of inclined tube is provided with pipe union for taking out dried uranyl hexahydro-nitrate crystals and wash solution feed union. Pipe union for taking out dried crystals is disposed above that wash solution feed union. Pipe union for feeding uranyl nitrate solution is level with wash solution feed union and with water seal.

EFFECT: enhanced cleaning efficiency and economic efficiency of process.

7 cl, 2 ex

Up!