RU2622395C1 - Method of purifying glycols from impurities - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of purification of glycols from carbonyl compounds and/or their acetals by contacting glycol polymer containing sulphocathionite resin with an acidic form, and pretreated amine with the general formula (1)

where R₁, R₂ can be the same or different and independently represent hydrogen and/or hydrocarbon group with the number of carbon atoms from 1 to 6 selected from aliphatic, aromatic and cycloaliphatic groups.

EFFECT: enables to reduce the content of carbonyl c ompounds and reduce colour indicator glycols.

18 cl, 1 dwg, 1 tbl, 5 ex

Description

FIELD OF THE INVENTION

The invention relates to the field of production of high-purity glycols, which are used for the production of poly- and oligoesters, polyurethanes, ethereal plasticizers and in other applications where increased demands are made on the purity, color and / or UV absorption of the product.

State of the art

Triethylene glycol (TEG) is obtained as a by-product along with diethylene glycol (DEG) and polyethylene glycol (PEG) by hydration of ethylene oxide to produce monoethylene glycol (MEG). One of the reasons for the color and chemical instability of TEG is the presence of harmful impurities of aldehydes and ketones (carbonyl compounds) in the product streams leaving the ethylene oxidation reactor.

In patent CA 673313, publ. 10.29.1963, it was proposed to brighten the TEG with the help of additional steaming (5 kg of water vapor / kg of raw materials). In this case, one part of the impurities escapes with steam, and the other part forms condensation products and remains in the still bottom liquid after TEG distillation in vacuum. Similarly, in patent JP 48003607, publ. 02/01/1973, describes the purification of a mixture of DEG and TEG by simple distillation, dilution of the distilled mixture with 10% H ₂ O, removal of added water in a stripping column at 190 ° C and subsequent distillation at 200 ° C. The resulting products are resistant to high temperatures. However, the above methods have the disadvantage associated with increased energy intensity due to the high values of the heat of vaporization of water and glycols.

A method according to SU 1803400, publ. 03/23/93, purification of lower glycols (DEG and TEG) from coloring impurities by treatment with N-Cl and N-Br-imides of dibasic acids or N-halogen derivatives of isocyanuric acid (0.02-1% wt.). The disadvantage of this method is the increased corrosion activity of N-halogen derivatives.

The second reason for the appearance of color in TEG is as follows. DEG, TEG, and PEG are capable of being oxidized by atmospheric oxygen to (hydro) peroxides. Since rectification of glycols takes place in a vacuum, there is always the possibility of partial contact of products with atmospheric oxygen. In this case, peroxides can decompose to carbonyl and carboxyl compounds. Thus, aldehydes and ketones can appear in glycols and regardless of their presence in the initial solution of ethylene oxide. It was shown that at relatively low temperatures (75 ° C) there is a very long induction period of autocatalysis of DEG oxidation to hydroperoxide. However, in the presence of radical initiators, this period is sharply reduced. Effectively reduces the ability of DEG to autooxidize the addition of 0.05% hydroquinone [Lloyd, W.G. The low temperature autoxidation of diethylene glycol // J. Am. Chem. Soc. Vol. 78 pp. 72-5 (1956)].

In the application JP 49051212, publ. 05/18/1974, a method for the purification of glycols in the presence of 400 ppm organic phosphite is published. For example, 400 ppm (ppm) (PhO) ₃ P was added to 1000 g of crude glycols (obtained by reaction of ethylene oxide with H ₂ O followed by removal of H ₂ O) and subjected to distillation, which provided 723 g of MEG, 115 g of DEG 82 g of TEG, and 45 g of tetraethylene glycol with Hazen color 5, 5, 15, and 40, respectively.

Similarly, in patent RO 92269, publ. 08/31/08, a decrease in the color of the TEG distillate to 20 and a sharp decrease in its acidity occurs when phenolic antioxidants are added to the distillation cube in an amount of 300-500 ppm.

In the method according to patent CS 254944, publ. 02/15/1988, especially pure TEG for pharmacy is obtained by molecular distillation in the presence of 0.02-0.06% 2,6-di-tert-butyl-4-methylphenol.

By the method specified in patent DE 19602116, publ. 07.24.1997, the formation of aldehydes during the rectification of mixtures containing glycols is suppressed by treating the columns with reducing phosphorus compounds, for example phosphorous acid. In a system for the production of glycols, H ₃ PO _{3 is} continuously introduced into the product stream before an MEG rectification column in an amount of 20 ppm. in relation to the flow of glycols. Equilibrium is achieved in 2 hours, MEG contains <10 ppm aldehydes. It has been argued that H ₃ PO ₃ inhibits iron oxides gradually forming inside ferrous metal columns in their catalysis of glycol oxidation. Also in the application JP 2013209329, publ. 10/10/2013, it is claimed that in the apparatus for rectification of TEG and tetraethylene glycol (distillation columns, boilers, pipelines), black mud is gradually accumulated, which is a catalyst for the oxidation of glycols. A method for cleaning equipment from deposits by acid washing (e.g., with oxalic acid) followed by treatment with a corrosion inhibitor (e.g., ammonium citrate) is described. At the same time, it is possible to obtain unpainted glycols practically free of aldehydes on purified equipment.

However, the disadvantage of the above methods of inhibiting the oxidation of glycols is that they work only when carbonyl compounds are not yet present in the feedstock. If aldehydes, ketones or their derivatives are present in the feed, then other methods for the purification of glycols are required.

In general, adsorption (chemisorption) methods for removing carbonyl compounds from products are most preferred. Such methods are energy efficient, do not contaminate products with extraneous chemicals, and make it possible to organize stream cleaning as a continuous technological process with short sorbent regeneration cycles.

In the method according to SU 187653, publ. 10/11/1966, it is proposed to remove aldehydes from solutions of organic substances with the help of sulfocationite treated with metal salts and hydrazine. The spent cation exchange resin is regenerated sequentially by flows of hydrogen peroxide, water, and hydrazine hydrate. The disadvantage of the proposed method is the use of toxic salts of transition metals (copper).

To remove aldehydes from water-glycol streams according to the method described in patent RU 2265584, publ. 12/10/2005, use anion exchange resin in the sulfite or hydrosulfite form. Aldehydes passing through hydrosulfite react with it to form bisulfite derivatives as shown below and are removed from the stream.

The resin can be regenerated by washing it with an excess of fresh bisulfite. The disadvantage of this method is the need for purification of glycols in an aqueous solution. Therefore, this method is mainly used for purification of cyclic water used for the absorption of ethylene oxide and the reaction of glycol synthesis.

A known method for the chemisorption removal of glucose (aldose) from a methanolic solution of methyl glucoside by contact with cation exchange resin treated with hydrazine hydrate according to the application JP 06100580, publ. 04/12/1994. Glucose (hemiacetal) reacts with hydrazine as a polymer sulfonate, while methyl glucoside (acetal) does not react with hydrazine cation in a neutral environment. In this case, hydrazone is formed from glucose in the form of a sulfone salt (A) with the release of water. Also, in the case of an excess of aldehyde or ketone, azine may form from hydrazone with the release of another equivalent of water (B).

A feature of this method, which does not allow it to be realized for the purification of glycols, is the need for the presence of aldehyde in free form or in the form of a semi-acetal, since complete acetals (e.g. methyl glucoside) are stable in a neutral environment of neutralized cation exchange resin.

Indeed, many reactive carbonyl compounds can be found in glycols in latent dioxolane form or be full acetals with MEG or heavy glycols.

However, if diols are not purified from acetals of carbonyl compounds, then, under the conditions of synthesis from the diols of a (poly) ether product using an acid catalyst and water liberation, the above form of carbonyl compounds is capable of further transformations with the formation of reactive compounds that determine the color of the target product.

In the method disclosed in patent FR 1598362, publ. 08/14/1970, described the improvement in the color performance of glycols due to contact with a strongly acidic ion-exchange resin at 80-100 ° C. The disadvantage of this method is the formation of high molecular weight resins irreversibly coking the catalyst, as well as insufficient improvement of quantitative indicators of color for TEG (color decreases from 130 units to 100 NaOH / APHA).

Closest to the developed method is a method for the purification of glycols described in application JP 2013129613, publ. 07/04/2013. Thus, in the aforementioned application, triethylene glycol containing a small amount (for example, 40 ppm) of an amine is contacted with a strongly acidic ion exchange resin. At the same time, the pH of the solution obtained after contacting is neutral, and the color is about 5 units. ARNA. The disadvantage of this method is the need for constant dosing in TEG amine, the amount of which is not obvious in advance. In addition, the description does not say about the nature of the dosed amine and the effect of cation exchanger on the content of carbonyl compounds bound in acetal.

Thus, known from the prior art methods for the purification of glycols are aimed only at solving the problem of removing aldehydes and / or ketones from glycols. However, in addition to aldehydes and / or ketones, such raw materials may contain acetals of aldehydes and / or ketones, which under certain conditions can be converted to aldehydes or ketones, for example, by the reaction below.

Known from the prior art methods for the purification of glycols do not solve the problem of extracting acetals from such raw materials. The presence of acetals in glycols does not affect the color index and the content of aldehydes and / or ketones in glycols. However, the further use of glycols containing acetals, for example, the use of monoethylene glycol in the production of polyethylene terephthalate (PET), results in a product characterized by an increased color index due to the indicated conversion of acetals.

Thus, one of the promising areas is the development of an effective method for the purification of glycols from aldehydes, ketones and their acetals.

Brief Description of the Drawings

FIG. 1 - Installation diagram for the purification of glycols from impurities of carbonyl compounds and / or their acetals.

In accordance with FIG. 1 raw material (glycol) is supplied from Capacity 1 to Adsorber 1 using Pump 1. The adsorber 1 is thermostatically controlled by Heat Exchanger 1. The raw materials are filtered from the residues of resin on Filter 1 due to pressure drop, then the resulting product flows by gravity into the product Capacity 2.

SUMMARY OF THE INVENTION

The present description of the invention relates to a method for the purification of glycols from carbonyl compounds and / or their acetals by contacting the crude glycol with a polymeric sulfocationite resin having an acid form and pre-treated with an amine with the general formula (1)

where R ₁ , R ₂ can be the same or different and independently represent hydrogen and / or hydrocarbon groups with the number of carbon atoms from 1 to 6, selected from aliphatic, cycloaliphatic and aromatic groups, while the treatment of sulfocationite resin is carried out at a molar the ratio of amine: sulfo groups in the range from 1:20 to 1: 1.

SUMMARY OF THE INVENTION

The present invention is to develop a method for the purification of glycols from impurities of carbonyl compounds and / or their acetals.

The technical result consists in reducing the content of carbonyl compounds, in particular aldehydes and / or ketones in glycols, from 200-300 ppm to 40-60 ppm (by 80%) and reducing the color index of glycols by 10-15 units.

The task and technical result are achieved by carrying out the process of purification of glycols from impurities of carbonyl compounds and / or their acetals by contacting the crude glycol with a polymeric sulfation cation exchange resin having an acid form and pre-treated with an amine with the general formula (1)

where R ₁ , R ₂ can be the same or different and independently from each other represent hydrogen and / or hydrocarbon groups with the number of carbon atoms from 1 to 6, selected from aliphatic, cycloaliphatic and aromatic groups. In this case, the processing of sulfocationic resin is carried out at a molar ratio of amine: sulfo groups in the range from 1:20 to 1: 1, preferably at a ratio of 1: 2. The use of less than 1:20 molar ratio is possible, however, it will reduce the chemisorption capacity of sulfationic resin. The use of a larger than 1: 1 molar ratio is also possible, however, the number of acid sites capable of catalyzing the cleavage of acetals of carbonyl compounds will decrease. As a result of this treatment, the polymer sulfocationite resin contains three types of groups, namely, the group —NR ₁ R ₂ , which provides the binding of the amino compound to the surface of the sulfationic resin; a —NH ₂ group that can react with a carbonyl compound to form a C = N double bond (hydrazone or Schiff base), and a —SO ₃ H group that acts as a catalyst for the reaction of acetals with a —NH ₂ group to form the corresponding hydrazone with the release of alcohols.

Below is presented (without limitation) a reaction scheme for the chemisorption of acetal of a carbonyl compound (A) and a 2,3-unsaturated carbonyl compound (B) on a sulfocationite resin treated with an amine:

The proposed method for the purification of glycols involves contacting a crude feed containing impurities of carbonyl compounds and / or their acetals with a heterogeneous adsorbent, which is a polymer sulfocationic resin pretreated with an amine.

Preferably, the contacting is carried out when the feed is a liquid mobile phase, while the adsorbent is a solid stationary phase.

Various glycols can be used as raw materials, including mono-, di-, tri-, tetraethylene glycol and ethylene glycol oligomers containing carbonyl compounds, in particular aldehydes and / or ketones, for example, methanal, ethanal, propenal (acrolein), hydroxyethanal (glycolaldehyde), O- (2-hydroxyethyl) hydroxyacetaldehyde, ethanedial (glyoxal), 2-butenal (crotonaldehyde), propan-2-one (acetone), 3-buten-2-one (methyl vinyl ketone), 3-methylcyclopentane -1,2-dion and others, capable under certain conditions of turning into acetals, for example, as presented below.

As the adsorbent, a polymer sulfocationic resin in acid form is used. The sulfocationite resin is preferably macroporous with a specific surface area of more than 5 m ² / g determined by low-temperature nitrogen adsorption (BET method), and is preferably a crosslinked poly- (styrene-divinylbenzene) -sulfonic acid and / or its salt.

Examples of suitable sulfocationic resins are, but are not limited to, sulfonic acid resins Amberlyst 15 WET (Dow Chemical), Amberlyst 35 WET (Dow Chemical), Amberlyst 36 WET (Dow Chemical), Axens TA 802 (Axens), Diaion RCP160M (Alfa Aesar) , Relite EXC8D (Resindion), Relite EXC134 (Resindion), Indion 190 (Ion Exchange), Indion 790 (Ion Exchange), Purolite CT-169 (Purolite), Purolite CT-169 DR (Purolite), Purolite CT-175 (Purolite ), Purolite CT-275 (Purolite), Tulsion T-62 (Thermax), Tulsion T-8052 (Thermax), Lewatit K 2621 (Lanxess), Lewatit K 2624 (Lanxess), Lewatit K 2625 (Lanxess), Lewatit MonoPlus SP 112 (Lanxess), Lewatit K 2629 (Lanxess), Resinex Cat-1 (Jacobi Carbons), Resinex Cat-2, (Jacobi Carbons), etc.

As an amine suitable for the treatment of sulfocationic resins, a compound with the general formula (1) is used

where R ₁ , R ₂ can be the same or different and independently from each other represent hydrogen and / or hydrocarbon groups with the number of carbon atoms from 1 to 6, selected from aliphatic, cycloaliphatic and aromatic groups. Specific examples of such compounds include, but are not limited to, hydrazine, methylhydrazine, ethylhydrazine, propylhydrazine, 1,1-dimethylhydrazine, N, N-methylethylhydrazine, benzylhydrazine, phenylhydrazine, 2,4-dinitrophenylhydrazine, and others. Hydrazine, methyl are most preferably used. and ethylhydrazine.

The amine treatment of the above sulfation cationic resins is a reaction of neutralizing the sulfo groups of the sulfation cationic resin with an amine. The degree of neutralization of sulfone centers (—SO ₃ H groups) in sulfocationite resin as a result of treatment with an amine can vary. So the degree of neutralization can vary from 0 (fully acid sulfocationic resin) to 1 (sulfocationic resin in salt form). Preferably, the degree of neutralization should be in the range of 0.3 to 0.9, more preferably in the range of 0.5 to 0.7, for the balance between the chemisorption capacity and the catalytic activity of the sulfation cation resin.

According to the present invention, the sulfocationic resin used can be obtained by a method comprising the step of suspending the sulfationic resin in a solvent, which include, but are not limited to, water, alcohols with the number of carbon atoms C _1-8 , etc., the stage of adding an amine to the suspension , the stage of decantation of sulfocationic resin, which is then used in the process of purification of glycols.

The suspension phase sulfonation resin is carried out at a temperature of from 0 to 120 ° C for 0, 1-24 hours at a temperature of the solvent from 0 to 120 ° C.

The amine addition step is carried out at a temperature of from 0 to 120 ° C. for 0.1-24 hours at an amine concentration of 0.1 to 10 mol / L.

Also, the treatment of sulfocationic resin can be carried out by ion exchange, passing through the resin aqueous solutions of amine salts (sulfate, chloride, etc.) in the corresponding molar ratio under conditions known from the prior art (US 3469940, publ. 30.09.1969).

The glycol purification process is carried out in any type of reactor known in the art. Suitable reactors are a flow mixing reactor, a batch reactor, an ideal displacement reactor, for example a tubular reactor. Preferably, the cleaning process is carried out in an adsorber. In this case, an adsorber is understood to be an apparatus in which gas and vapor components (adsorbents) are absorbed from liquid or gas mixtures by the surface layer of an adsorbent — a solid substance, on the surface or pores of which adsorption (absorption) occurs. During operation of the adsorber, regeneration of the adsorbent is often necessary, that is, removal of the adsorbed substance (adsorbate) from its pores.

In a preferred embodiment of the method, the adsorber is an adsorption column with a top (gravity flow) or bottom (under hydrostatic pressure) supply of a purified liquid stream.

The glycol purification process is carried out at a temperature of from 0 to 120 ° C, preferably from 20 to 100 ° C, most preferably from 40 to 90 ° C. At the temperature mentioned above, the sulfation cation resin will catalyze the interaction of impurities with the amine on the adsorbent with the release of water or alcohols (glycols), while the process of decomposition, reaction and removal of impurities will be the most active and selective. The process of contacting the raw material with the adsorbent at higher temperatures (above 90 ° C) can lead to side processes, such as polymerization of glycol with the release of water, alkylation of the amine with alcohol groups of glycols, etc.

The feed stream entering the adsorber reactor is heated or cooled to the desired temperature by passing it, for example, through a heat exchanger. The choice of temperature to which the incoming stream is adjusted is carried out taking into account the fact that the contacting of the feed stream with the adsorbent occurs predominantly in the isothermal mode.

In accordance with the proposed method, the reaction time may vary. The reaction time can be defined as the residence time of the volume of raw materials in the volume of the reaction zone of the adsorber and expressed in units of the inverse time. The reaction time varies depending on the raw materials used, the reaction temperature, the type of impurities and other process parameters. In embodiments of the method, the reaction time may be at least 0.05 h ^-1 . The reaction time can be at least 0.1 h ^-1 , at least 0.2 h ^-1 , at least 0.5 h ^-1 , at least 1 h ^-1 , at least 2 h ^-1 , not less than 5 h ^-1 , not less than 10 h ^-1 . The most preferred reaction time is from 0.5 to 2 h ^-1 .

According to the proposed method, the purified glycol stream may additionally come into contact with an additional adsorbent, which may be located before or after the main adsorbent. An additional adsorbent can clear the stream of traces of amines and further improve the color performance of glycol. In addition, an additional adsorbent can lead to an increase in the resource of the main adsorbent. The sulfonic cation resin, activated carbon, silica gel, etc. can act as an additional adsorbent. The stream entering the additional adsorber can be heated or cooled to a temperature of 0 to 100 ° C, preferably to a temperature of 0 to 50 ° C, more preferably to temperatures from 20 to 40 ° C, by passing it, for example, through a heat exchanger.

According to the proposed method, the stream leaving the reactor is a purified glycol, which is a commercial product.

Examples

As the feedstock used triethylene glycol (TEG) grade B, containing up to 0.03% of the mass. (300 ppm) aldehydes in terms of acetaldehyde.

Example 1. The method of analysis for the content of acetals

1. Preparation of a standard solution of acetaldehyde

Prepare an initial solution of acetaldehyde in 50% ethanol solution according to GOST 4212 p. 3.2. It is preferable to prepare a solution of a high concentration in a 100 ml volumetric flask (4-5 mg / ml) since acetaldehyde has a low boiling point and is a highly volatile substance. Acetaldehyde is poured into a small amount of solvent, and then adjusted to the mark.

2. Determination of the exact concentration of the standard solution

In a conical flask with a capacity of 50 ml, pipette 10 ml of a standard solution of acetaldehyde, add 25 ml of ethyl alcohol, and mix. Using an ionomer or indicator paper, the pH of the solution is adjusted to pH = 4.0 with a solution of sodium hydroxide at a concentration of 0.1 mol / L (0.1 N) or with a solution of hydrochloric acid at a concentration of 0.05 mol / L (0.05 n).

To the solution add 5 ml of a solution of hydroxylamine hydrochloride (concentration (C) p-pa = 5% by weight), mix, close and leave alone for 30 minutes. Then titrated with a solution of sodium hydroxide concentration of 0.1 mol / l (0.1 n).

At the same time, under the same conditions, a control experiment is carried out using distilled water instead of acetaldehyde solution.

Calculate the mass concentration of acetaldehyde in a standard solution (C1), mg / ml, according to the formula

,

,

where V is the volume of a solution of sodium hydroxide concentration of 0.1 mol / l (0.1 n), which went to the titration of a solution of acetaldehyde, ml;

Vk is the volume of a solution of sodium hydroxide concentration of 0.1 mol / l (0.1 n), which went to the titration in the control experiment, ml;

0.0044 - the mass of acetaldehyde corresponding to 1 ml of a solution of sodium hydroxide concentration of 0.1 mol / l (0.1 n), g;

k is the correction coefficient of the sodium solution concentration of 0.1 mol / l (0.1 n);

B is the volume of a standard solution of acetaldehyde taken for measurement, ml;

1000 - conversion factor g in mg.

At least three parallel measurements are performed and the arithmetic average of the mass concentration of acetaldehyde in the standard solution is calculated.

3. Establishment of calibration characteristics.

Prepare a dilute standard solution of acetaldehyde with a concentration of C2 = 0.4-0.5 mg / ml in a 100 ml volumetric flask.

When constructing a calibration graph perform the following operations:

Comparison solutions are prepared.

In a series of volumetric flasks with a capacity of 50 ml, place a pipette 0; 0.5; one; 2; 3; four; 5 ml of diluted standard acetaldehyde solution. Dilute the contents of the flasks with a 50% solution of ethyl alcohol and make up to the mark.

Next, 2 ml of each standard and 2 ml of 2,4-dinitrophenylhydrazine solution are pipetted into volumetric flasks with a capacity of 2.5 ml. The closed flasks are kept at room temperature in the dark for 30 ± 2 minutes, after which they are diluted to the mark with a potassium hydroxide solution and the contents are thoroughly mixed.

After 12 ± 1 minutes of standing on the table after adding potassium hydroxide, the light absorption of each solution is measured at a wavelength of 480 nm in 1 cm cell.

The absorption of the solution due to the carbonyl compound in the sample is calculated by subtracting the absorption of the blank solution (calibration solution number 1).

Two ml of each solution contains acetaldehyde, (S) mcg:

,

,

where C2 is the concentration of the diluted standard solution, ml;

Va is the aliquot volume, ml;

Vk is the volume of the flask, ml;

1000 - mg to μg conversion factor.

Based on the data obtained, the dependence of absorption on the amount of acetaldehyde in micrograms is built.

Perform analysis.

Before performing the analysis, it is necessary to prepare a sample.

About 10 g of technical triethylene glycol is weighed, recording the weighing result in grams to the second decimal place. A sample of the product is placed in a 100 ml conical flask, 12.5 ml of a 1M sulfuric acid solution are added and left for 30 minutes, then the contents of the flask are neutralized with a 1M sodium hydroxide solution to pH = (6-7) using universal indicator paper or on an ionomer.

In a volumetric flask with a capacity of 2.5 ml, transfer 2 ml of the prepared sample with a pipette, weigh it to the fourth decimal place, and add 2 ml of a solution of 2,4-dinitrophenylhydrazine. The closed flask was kept at room temperature in the dark for 30 ± 2 minutes, after which it was diluted to the mark with a solution of potassium hydroxide and the contents were thoroughly mixed.

After 12 ± 1 minutes of standing on the table after adding potassium hydroxide, the light absorption of the solution was measured at a wavelength of 480 nm in 1 cm cell.

The absorption of the solution due to the carbonyl compound in the sample is calculated by subtracting the absorption of the blank solution. To prepare a blank solution, distilled water is used instead of the sample.

The content of acetaldehyde in micrograms is determined by the calibration graph.

The mass content of aldehydes in terms of acetaldehyde, X,%, is calculated by the formula

;

;

where A is the mass of acetaldehyde found according to the calibration graph, mcg;

B is the mass of the analyzed sample, taken for determination, g;

10 ⁴ - the ratio of the conversion factor in percent to the conversion factor mcg in

Recalculation of concentration, Ch,%, on a pure product is carried out according to the formula:

;

;

where Mr-ra - the total mass of the solution, after sample preparation, g;

X - mass content of aldehydes in terms of acetaldehyde,%;

Mp - the mass of pure product taken for preparation,

Chroma was determined on a LOVIBOND-PFXi-995 automatic colorimeter.

Example 2. Adsorption by aluminosilicate AS-230Sh

The B grade triethylene glycol (TEG) (250 ml) is loaded with AC-230Sh adsorbent (100 g). Shake on a laboratory shaker for 24 hours, then filter. The glycol aldehyde content is 277 ppm.

The example data show that selective adsorption of acetal components on an aluminosilicate adsorbent does not occur.

Example 3. The treatment of sulfocationic resin with hydrazine

Amberlyst 36W sulfation cationic resin (100 ml of an aqueous resin containing 0.195 mol of sulfo groups in the H-form) is suspended in hot freshly distilled TEG (1000 ml), stirred at 100 ° C for 2 hours, the TEG is decanted, the operation is repeated several times until the TEG is visually visible ceases to stain (contaminated TEG regenerate by vacuum distillation). Add 5 g of 100% hydrazine hydrate (0.1 mol) in 500 ml of TEG, stir for 2 to 4 hours at room temperature. The sulfation cationic resin is decanted and transferred to an adsorber. The volume of the swollen sulfocationite resin is about 150 ml.

Example 4. Purification of TEG by contacting with a sulfocationic resin treated with hydrazine

Assemble the installation with thermostating the adsorber and continuously pumping TEG brand B through the adsorbent (Fig. 1). Amberlyst 36W cation exchanger, partially (50% molar) neutralized with hydrazine, is used as an adsorbent. To exclude color leakage in the form of desorbed hydrazone and azines, an optional additional adsorber is introduced into the circuit. As an additional adsorbent, TEG-saturated Amberlyst 36W cation exchanger in the H-form is used. Table 1 (lines 1-7) shows the contact conditions and analysis data of the TEG fractions as they exit the adsorber.

Also in lines 6 and 7 are the results of contacting the fractions with an additional adsorbent. It is noticeable that in the absence of an additional filter, the color of the product is higher.

Example 5. Purification of TEG by contacting with piperazine-treated sulfocationic resin

Acted as in example 4, only to neutralize the cation exchanger took 25% molar piperazine. The color of the product immediately after contacting was 300 units. Pt-Co and above. Work after pumping 0.5 l of TEG was stopped.

From the results of the experiment it is seen that the purification of the raw material by contacting with a sulfocationic resin treated with hydrazine can significantly reduce the content of carbonyl compounds and the color of the product (lines 1 and 2 of Table 1).

In this case, the best result is achieved when passing through sulfocationic resin raw materials in a volume of up to 3-4 liters. After a certain volume of raw materials (3 + 1 L), which is subjected to contact with a sulfocationite resin, the content of carbonyl compounds and the color of the product gradually increase (lines 3–7 of Table 1).

In order to better improve the color of the product, it is possible to use an additional acid adsorbent, which allows you to remove part of the colored impurities and, as a result, reduce the color of the product (lines 6-7 of Table 1).

Claims (22)

1. The method of purification of glycol from carbonyl compounds and / or their acetals by contacting the glycol with a polymer sulfocationic resin having an acidic form and pre-treated with an amine with the General formula (1)

where R ₁ , R ₂ can be the same or different and independently from each other represent hydrogen and / or hydrocarbon groups with the number of carbon atoms from 1 to 6, selected from aliphatic, cycloaliphatic and aromatic groups. 2. The method according to p. 1, where the processing of the polymer sulfocationic resin is carried out at a molar ratio of amine: sulfo groups in the range from 1:20 to 1: 1. 3. The method according to p. 2, where the processing of the polymer sulfocationic resin is carried out at a molar ratio of amine: sulfo group 1: 2. 4. The method according to claim 1, where mono-, di-, tri-, tetraethylene glycol and ethylene glycol oligomers can be used as glycol. 5. The method according to claim 1, where the polymer sulfocationic resin is macroporous. 6. The method according to p. 1, where the polymer sulfocationic resin has a specific surface area of more than 5 m ² / g, determined by the method of low-temperature nitrogen adsorption. 7. The method according to p. 1, where the polymer sulfocationic resin is a crosslinked poly- (styrene-divinylbenzene) -sulfonic acid and / or its salt. 8. The method according to claim 1, wherein the amine is a compound selected from the group consisting of hydrazine, methylhydrazine, ethylhydrazine, propylhydrazine, 1,1-dimethylhydrazine, N, N-methylethylhydrazine, benzylhydrazine, phenylhydrazine, 2,4-dinitrophenylhydrazine. 9. The method according to p. 1, where the polymer sulfocationic resin is obtained by a method comprising the step of suspending the sulfation cation resin in a solvent, the step of adding an amine to the suspension, the step of decanting the sulfation cation resin. 10. The method according to p. 9, where the solvent is water and / or alcohols with the number of carbon atoms from 1 to 8. 11. The method of claim 9, wherein the step of suspending the sulfation cation resin is carried out at a temperature of from 0 to 120 ° C. for 0.1-24 hours at a temperature of the solvent from 0 to 120 ° C. 12. The method according to p. 9, where the stage of adding an amine is carried out at a temperature of from 0 to 120 ° C for 0.1-24 hours at an amine concentration of from 0.1 to 10 mol / L. 13. The method according to p. 1, where the glycol is purified from carbonyl compounds and / or their acetals is carried out at a temperature from 0 to 120 ° C, preferably from 20 to 100 ° C, most preferably from 40 to 90 ° C. 14. The method according to p. 1, where the contact time of the glycol with the polymer sulfocationite resin is from 0.5 to 2 h ^-1 . 15. The method of claim 1, wherein the glycol is contacted with an additional adsorbent. 16. The method according to p. 15, where as an additional adsorbent use an adsorbent selected from the group including sulfocationic resin, activated carbon, silica gel. 17. The method according to p. 15, where the contacting of the glycol with an additional adsorbent is carried out before or after contacting the glycol with a polymer sulfocationic resin having an acid form and pre-treated with an amine with the general formula (1)

where R ₁ , R ₂ can be the same or different and independently from each other represent hydrogen and / or hydrocarbon groups with the number of carbon atoms from 1 to 6, selected from aliphatic, cycloaliphatic and aromatic groups. 18. The method according to p. 15, where the glycol is preheated or cooled to a temperature of from 0 to 50 ° C, more preferably to a temperature of from 20 to 40 ° C.

Images