The method of separation of anhydrous sodium formate from aqueous solutions
(57) Abstract:Usage: anhydrous sodium formate from aqueous solutions in the production of polyhydric alcohols with the use of azeotropic distillation with aromatic hydrocarbons. Essence: for dehydration of salt as azeotroping agent used benzene, toluene or xylene. The aqueous layer obtained azeotropic mixture is directed to the main stage of obtaining alcohol, and the organic layer is repeatedly used in the refining process. The volumetric ratio of aqueous solution of salt and azeotropically equal to (1-1,5) : 2. The invention relates to the field of production of anhydrous sodium formate used in leather, textile and construction, which is a byproduct in the synthesis of polyhydric alcohols, condensation of the aldehyde in an alkaline medium. The specified method in the industry get pentaerythritol, atrial (trimethylolpropane), neopentylglycol (2,2-DIMETHYLPROPANE-1,3). When this method is used for 1 mol of the organic alcohol produces 1 mol of salt. In this regard, to obtain commercial sodium formate from the reaction solution remaining after separation of the alcohol, is an important task. Ø the capacity of the salt in water at low temperatures. In addition, aqueous solutions of sodium formate falls in the form of a hydrate dehydration which is carried out at elevated temperatures.There is a method of separation and drying of sodium formiate method evaporative crystallization in a fluidized bed using flue gases with a temperature of 300-350o(Y. A. Kaganovich, A., Slabinski "Industrial installations for drying in a fluidized bed", L. Chemistry, 1970, page 175). The disadvantages of this method are complex instrumentation process, high energy costs and low quality of formate sodium contaminated flue gases and the products of oxidation at high temperatures by-products of the synthesis of alcohols, which are present in the solutions received for processing.Prototypes to this application are the following.In the patent Poland 131946, class C 07 C 53/06//C 07 C 31/24 applied to the synthesis of pentaerythritol on anion exchangers offer the following scheme of producing sodium formate. The aqueous solution after regeneration of the anion exchange resin containing 2.1 to 3.9% of sodium formate, 0,9 2,1% sodium hydroxide concentrate, removing up to 90% of water, mixed with 25-50% methanol, boiled for 30-60 min, cooled and produce sodium formate. Methanol return tov, obtained by condensation of aldehydes in the presence of sodium hydroxide, proposed a similar approach, but expanded the range of solvents. In this case, use solvents, miscible with water, methanol, ethanol, dioxane). They are administered in an aqueous solution in an amount up to 60% salt produce crystallization. The solvent to be regenerated before reuse in the process. Salt is subjected to drying.The drawback of both methods is the need of the organization phase of regeneration of organic solvents from aqueous solutions containing sodium formate. The last you want to retrieve from still bottoms and recycle them into marketable products.As to how the selection of sodium formiate in the synthesis of neopentyl glycol, they have not been studied, because most often, the synthesis is carried out only with a catalytic amount of base type tertiary amines, and restore aldos conduct a hydrogenation catalyst.An object of the invention is to develop a method of producing anhydrous sodium formiate in the synthesis of polyhydric alcohols with the exception of the operation of the regeneration of the solvent, increasing the purity of the salt and simplified the s from solutions of sodium formate is carried out in the form of an azeotropic mixture, and the solvent is selected based on the requirements of having a separate azeotropic mixtures and minimum solubility in water. These requirements satisfy, for example, aromatic hydrocarbons benzene, toluene, xylene, etc. giving azeotropic mixture with water, divided ambient temperature in aqueous and organic layers. The developed method consists in the following.To aqueous solution of sodium formiate, obtained after extraction of polyhydric alcohols (atrial, pentaerythritol, neopentyl glycol), add solvent (benzene, toluene, xylene and others). The resulting mixture is heated with stirring, providing a constant boiling and distillation of water. After condensing the azeotropic mixture is sent to the divider, where the solvent back into the process, and water is collected in the collection. After distillation of the water suspension of anhydrous sodium formiate is filtered, the product is dried, and the solvent is sent without regeneration for the next process. Water, distilled from formate, used in the synthesis of polyhydric alcohols without any additional training. The amount of solvent required for the operation of distillation, is determined by the amount of equipment and technological properties of p is hladiny. Hot filtering allows you to further purify the sodium formate impurities alcohol if present in the solution.The essence of the above proposals is illustrated by examples.Example 1. In a flask equipped with stirrer, thermometer and a trap Dean-stark connected with a reflux condenser, pour 150 ml of an aqueous solution of sodium formiate, (density 1,272 g/cm) obtained after the extraction of neopentyl glycol and 200 ml of toluene. Carry out the distillation of water in the form of an azeotropic mixture with toluene, carrying out the temperature control in pairs and measuring the amount of water in the trap. At the end of the process, the suspension is cooled, the sodium formate is filtered off and dried. The product yield and water is practically quantitative. The melting point of salt 260-265oC. Content of sodium formiate of 99.1% content neopentyl glycol 0.4% Results with other similar solvents.Example 2. Conditions of experience as in example 1. Taken 100 ml of solution with a density of 1.27 g/cm, obtained in the synthesis of pentaerythritol, and 200 ml of toluene. The resulting sodium formate with a melting point 247 - 250oWith, the product yield and water settlement. The content of sodium formate 97%
Example 3. Conditions of experience as in example 1. Taken 150 ml rozvody quantitative. The melting point of the obtained sodium formate 258-260oC. the Content of sodium formiate 98,7% The method of separation of anhydrous sodium formate from the aqueous solution after extraction of polyols obtained by the condensation of aldehydes with formaldehyde, by removing water by azeotropic distillation, characterized in that the dehydration salts are using benzene, toluene or xylene as azeotroping agent and the aqueous layer azeotropic mixture is directed to the main stage of obtaining alcohol, and the organic layer is repeatedly used in the refining process.
FIELD: ecology; hydrochemistry; analytical chemistry; methods of extraction of the volatile organic substances from the water medium.
SUBSTANCE: the invention is pertaining to the field of ecology, hydrochemistry, analytical chemistry and may be used for extraction of the organic compounds from the water mediums, in particular, from the mineral waters including sulfide mineral waters. For realization of the method of extraction of the volatile organic substances from the water medium into the organic dissolvent conduct the joint condensation of the extracted substance produced as a result of distillery and the vapor of the dissolvent. For production of the joint condensate they gate the vapor-shaped dissolvent through the water sample or preliminary add it into the water sample with the subsequent distillation. The organic dissolvent is chosen from the following row: ethanol, acetonitrile, acetone, hexane. The method ensures the single-stage extraction of the dissolved organic substances into the dissolvents, the unlimited their mixing with the water, reduction of the thermal action on the researched sample, the increase of the extraction ratio.
EFFECT: the invention ensures the single-stage extraction of the dissolved organic substances into the dissolvents, their unlimited mixing with the water, the reduced the thermal action on the researched sample, the increased extraction ratio.
2 cl, 1 tbl, 5 ex
SUBSTANCE: method of separation of starting mixture (A) consisting of two or more constituents, by extractive distillation with the selective solvent (S) within dividing wall column (TKW), is proposed. The separation is performed in the dividing wall column (TKW) having a dividing wall aligned in a longitudinal direction (TW) and extending to an upper end of the column and dividing an interior of the column into first region (1), second region (2), and lower combined column region (3). The starting mixture is fed into first region (1), first top stream (B) is taken off from first region (1), and second top stream (C) is taken off from second region (2), with each of the streams having a prescribed specification. The selective solvent (S) is introduced in an upper part of first region (1) and/or in an upper part of second region (2), and flow of solvent (S1) into the first region (1) and/or flow of solvent (S2) into second region (2) are set so that each of the prescribed specifications for top streams (B, C) are met.
EFFECT: invented method of dividing mixtures is more efficient in terms of energy and solvent consumption.
6 cl, 7 dwg, 1 tbl
SUBSTANCE: invention concerns improved method for obtaining (meth)acrylic acid involving steam phase catalytic oxidation of propylene, propane or isobutylene for production of reaction mix, absorption of oxidised reaction product in water to obtain water solution containing (meth)acrylic acid, concentration of water solution in the presence of azeotropic agent and distillation of obtained (meth)acrylic acid in distillation column to obtaining purified (meth)acrylic acid. During operation of distillation column, including operation interruption and resumption, the column is washed with water, and afterwards azeotropic distillation is performed in the presence of azeotropic agent.
EFFECT: efficient and fast cleaning of distillation column with extraction of valuable substance.
5 cl, 5 dwg, 3 ex
SUBSTANCE: invention relates to chemical engineering, particularly to obtaining dehydrated ethanol from synthetic alcohol. The method of dehydrating ethanol via extractive rectification with ethylene glycol in one composite column, in which the composite column has a side fastening section consisting of 3 t.t, and the main column has 21 t.t, the reflux ratio in the main column and the side section is equal to (0.33-0.38) and (0.11-0.15), respectively, with extraction of ethanol in the distillate of the main column, and ethylene glycol in the still bottom, which is returned for reflux to the third plate of the main column, and water in the distillate of the side section.
EFFECT: invention enables to obtain ethanol and water of higher quality and reduce power consumption by 20,1% compared to the prototype scheme with the same ratio of the starting mixture to ethylene glycol.
SUBSTANCE: to separate a biazetropic mixture butylpropionate-propionic acid used is a method of extractive rectification with application as a separating agent of sulpholane (SF), taken in ratio 1:5-6 to an initial mixture in a column of extraction rectification with efficiency 35-50 t.t., with reflux ratio in the column being 1-3. Withdrawal of butylpropionate in distillate and the mixture propionic acid-sulpholane in the column bottom is carried out. After that, the mixture PC-SF is supplied to the column of the separating agent regeneration with efficiency 8 t.t., value of reflux ratio is 0.5-1.0. The separating agent is withdrawn from the column bottom and supplied into the column. Pressure in the columns constitutes 100 mm Hg. The method makes it possible to obtain the target products (BP, PA) of a specified quality - 99.5 mol%.
EFFECT: simplification of technology and reduction of capital expenditure, increased quality of obtained products.
1 dwg, 1 tbl
SUBSTANCE: method of inhibiting polymerisation of vinyl aromatic compounds during extractive distillation includes the following steps: a) providing a mixture containing styrene; b) adding one 2-sec-butyl-4,6-dinitrophenol (DNBP) inhibitor to the mixture; and c) performing extractive distillation of the mixture after step b) to of separate styrene; d) forming less than 200 ppmw of a polymer from the styrene.
EFFECT: minimum polymer formation.
5 cl, 1 tbl, 1 ex
FIELD: power engineering.
SUBSTANCE: invention is intended for extraction distillation. Device for extraction distillation of the extract from the flow of raw material comprises the extraction distillation column, raw material flow supply line, solvent supply line, reboiler with internal steam distributor, connected with the extraction distillation column, water steam supply line, connected with the steam distributor, and water steam supply line from the extraction distillation column, connected with the internal steam distributor. The extract is an aromatic hydrocarbon. Reboiler is selected from the group consisting of the kettle boiler, thermosyphon reboiler and reboiler with forced circulation.
EFFECT: improvement of efficiency of extraction distillation.
10 cl, 1 dwg, 1 ex
SUBSTANCE: invention relates to versions of a method for the extraction of styrene and support of an extraction solvent efficiency in a system for styrene extraction from a styrene-enriched raw material. One of the versions includes the following stages: (a) supply of the styrene-enriched raw material into an extraction distillation column, (b) discharge of the styrene-enriched flow from the extraction distillation column, with the styrene-enriched flow containing styrene and an extraction solvent; (c) supply of the styrene-enriched raw material into the column for the solvent separation, d) discharge of the styrene-depleted flow from the column for the solvent separation, with the quantity of styrene in the styrene-depleted flow being lower than in the styrene-enriched flow; e) separation of a part of the styrene-depleted flow, f) bringing a part of the styrene-depleted flow in contact with an organic solvent in an equilibrium liquid-liquid system, which has several equilibrium stages, with the formation of a washed extraction solvent, containing the light organic phase and the heavy organic phase, with the light organic phase passing to the following equilibrium stage and the heavy organic phase returning to the first equilibrium stage; and g) recycling the washed extraction solvent back to the extraction distillation column.
EFFECT: method makes it possible to use solvents in a rational way.
17 cl, 4 dwg
SUBSTANCE: method of separating a zeotropic mixture of butyl propionate and propionic acid, components of which have relative volatility close to one, includes separating said mixture by extraction rectification using sulpholane as the parting agent, taken in ratio of 1:6-7 to the starting mixture in an extraction rectification column with efficiency of 40-50 theoretical plates, wherein the reflux ratio in the column is equal to 2-3, followed by collection of butyl propionate in the distillate and the mixture of propionic acid and supholane in the bottom of the column (1); the mixture of propionic acid and sulpholane is then fed into a column for regenerating the parting agent (2) with efficiency of 8 theoretical plates and reflux ratio equal to 0.8-1; the parting agent is removed from the bottom of the column (2) and fed into column (1). Pressure in column (1) is equal to 760 mmHg and pressure in column (2) is equal to 100 mmHg.
EFFECT: simple technique, low capital costs and high quality of the obtained products.
1 dwg, 1 tbl
SUBSTANCE: invention relates to chemical industry. Method involves separation of a five-component mixture, which is carried out in circuits, including one or two three-column complexes of extractive distillation. Separating agents used are sulpholane and dimethylsulphoxide. In first version sulpholane is fed into first column of separation circuit and into first column of three-column complex, and dimethyl sulphoxide is fed into first column of two-column complex for processing mixture of methanol-tetrahydrofuran as obtained distillate. In second version sulpholane is fed into first column of first three-column complex, and dimethyl sulphoxide is fed into first column of second three-column complex for processing mixture of methanol-tetrahydrofuran-water as obtained distillate. Composition of initial mixture is equimolar, amount of separating agent to initial mixture ranges from 0.2:1 to 2.5:1, reflux varies within range of 0.1-3.5.
EFFECT: invention provides for extraction of all components of said five-component industrial mixture of solvents and reduced power consumption.
1 cl, 2 dwg, 2 tbl, 2 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