CN1246275C - Reaction extraction process for extracting lower polybasic alcohol from thin aqueous solution - Google Patents

Abstract

The invention discloses a novel reactive extraction process for extracting low-level polyols from dilute aqueous solution, which belongs to the technical field of chemical separation. The reactive extraction process is a new type of reactive extraction method in which the reactant and the extractant are the same substance. Polyols and aldehydes are acetalized to form cyclic acetals. Aldehydes that are partially miscible with water are selected as the reactant and extractant, so that no additional new organic solvents need to be introduced, and the process is simple. The boiling point of selected aldehydes will be lower than water, and when using distillation or rectification method to reclaim aldehydes from raffinate phase like this, aldehydes are obtained from distillate, and energy consumption is low, and the impurity in water phase can be kept in water phase simultaneously and is separated, which is more important for complex systems containing a large amount of impurities such as fermentation broth.

Description

A Novel Reactive Extraction Process for Extracting Lower Polyols from Dilute Aqueous Solutions

technical field

The invention belongs to the technical field of chemical separation, and in particular relates to a novel reactive extraction process for extracting low-level polyols from dilute aqueous solutions.

Background technique

1,3-propanediol (1,3-Propandiol, referred to as Pdo) is a monomer for the production of polytrimethylene terephthalate (PTT). In the literature "Witt U; Muller RJ; Augusta J, et al, Synthesis properties and biodegradability of polyesters based on1,3-propanediol" of J, Makromol Chem Phys, 1994, 195:793-802" and "Appl Microbiol Biotechol, 1999, 52, 289-297 "Biebl H; Menzel; K, Zeng A-P, et al, Microbial production of 1,3-propanediol" reported that PTT is a polyester material with excellent performance, and the current Pdo production The methods mainly include the acrolein method and the ethylene oxide method, but these two methods have problems such as many side reactions, harsh reaction conditions, and environmental pollution, and the output is small, which greatly restricts the production and application of PTT. More and more attention has been paid to the advantages of mild conditions, renewable resources for production, and less environmental pollution.

Qi Wentao and Xiu Zhilong published in "China Biotechnology Journal, 2003, 23, 64-68" "Research Progress on Metabolism and Gene Regulation Mechanism of Glycerol Disproportionation to Produce 1,3-Propanediol" and Zhang Jian, Zhao Hongying, Liu Hongjuan et al. "Studies on Fermentative Production of 1,3-Propanediol Using Glucose as an Auxiliary Substrate" published in "Modern Chemical Industry, 2002, 22, 32-35" showed that using glycerol or glycerol fermentation broth and glucose as raw materials, the use of Klebsiella pneumonia When bacterial strains such as bacillus (Klebsiella pneumoniae) are fermented, the concentration of 1,3-propanediol in the fermentation liquid is about 5% when the fermentation ends. At the same time, the fermentation broth also contains many by-products such as acetate, lactate, succinate, glycerin, ethanol, 2,3-butanediol, bacteria and residual culture medium. In order to extract 1,3-propanediol, glycerol, and 2,3-butanediol from the fermentation broth, these substances must be separated from water and impurities.

Existing methods for separating and extracting lower polyols such as 1,3-propanediol from dilute aqueous solution or fermented liquid mainly include:

1. Concentrated distillation method, first directly distill and concentrate the fermented liquid with bacteria; after cooling, add ethanol or methanol, n-propanol, isopropanol, acetone, butanone, etc. in a certain proportion, and then precipitate by sedimentation or filtration or centrifugation , take the supernatant; then wash the precipitate with the same alcohol or ketone, then separate the precipitate by sedimentation or filtration or centrifugation, and get the supernatant; the resulting supernatant is recovered by distillation or rectification for alcohol or ketone (Xiu Zhilong; Zhang Daijia ; Gao Sujun, etc., the method for extracting and separating 1,3-propanediol from microbial fermentation broth CN14606712003.12.10).

2. Using the ion exchange method, the fermented liquid is passed through a cation exchange resin, and then eluted with a solvent to collect 1,3-propanediol components (Hilaly; Ahmad K; Binder; Thomas P., Method of recovering 1,3-propanediol from fermentation Broth, US 6,479,716, November 12, 2002; Roturier; Jean-Michel; Fouache; Catherine; Berghmans; Elie, Process for the purification of 1,3-propanediol from a fermentation medium, US 6,428,992, August 6, 2002).

3. Alkali adjusts the pH of the fermentation broth, and then separates it by other methods, including distillation, rectification, filtration, extraction and crystallization (Ames; Tyler T., Process for the isolation of 1,3-propanediol fromfermentation broth US 6,361,983, March 26, 2002).

4. Extract 1,3-propanediol from fermentation broth using simple liquid-liquid extraction of alcohols (Janusz J.Malinowski, Evaluation of liquid extraction potentials for downstream separation of 1,3-propanediol, Biotechnology Techniques 13:127-130, 1999.) .

5. Use ion-pair extraction to extract 1,3-propanediol from fermentation broth (Robert R. Broekhuis, ScottLynn, and C. Judson King, Recovery of Propylene Glycol from Dilute Aqueous Solutions by Complexation with Organoboronates in Ion-Pair Extractants, Ind. Eng. Chem. Res. 1996, 35, 1206-1214).

6. Use formaldehyde, acetaldehyde and 1,3-propanediol or other lower polyols to react, and the product is extracted with an organic solvent and then reduced (Robert R. Broekhuis, Scott Lynn, and C. Judson King, Recovery of Propylene Glycol from Dilute Aqueous Solutions viaReversible Reaction with Aldehydes, Ind.Eng.Chem, Res.1994, 33, 3230-3237; Janusz J.Malinowski, ReactiveExtraction for Downstream Separation of 1,3-Propanediol, Biotechnol.Prog.2000, 16, 76-79; .Malinowskil, and Andrew J.Daugulis, The effective approach for recovery of methyl-substituted 1,3-dioxane from aqueous media, separation science and technology, 37(11), 2659-2667(2002); Xiang Botao, Chen Shufeng, Andy Lau, Fermentation Extraction and separation of 1,3-propanediol in liquid, Journal of Tsinghua University (Natural Science Edition) 2001, 41(12)53-55).

For the above-listed method for extracting 1,3-propanediol or other low-level polyols from dilute aqueous solutions, there is a large energy consumption in methods 1 and 3, and the disadvantages of consuming a large amount of organic solvents; methods in 2 and 4 have poor industrial feasibility The extraction agent price used in the method in 5 is high, and the regeneration of the extraction agent is complicated; the method formaldehyde and acetaldehyde in the 6 have low boiling points, and are easy to form multimers and are difficult to recover, and use organic solvents such as benzene to extract more toxic.

Contents of the invention

The purpose of the present invention is to provide a novel reactive extraction process for extracting lower polyols from dilute aqueous solutions. It is characterized in that: the reactive extraction process is a novel reactive extraction method in which the reactant and the extractant are the same substance, and the process of extracting low-level polyols from dilute aqueous solution is as follows:

1. Use an acid to adjust the pH of the dilute aqueous solution containing lower polyols to be less than 3; or use a cation exchange resin to catalyze the acetal reaction.

2. Add 5wt% to 100wt% propionaldehyde, butyraldehyde, isobutyraldehyde or isovaleraldehyde of the solution to the dilute aqueous solution, so that the aldehydes can form a single phase as an extractant.

3. After reacting aldehydes dissolved in dilute aqueous solution with lower polyols at -10-60°C for 0.2-24 hours, a cyclic acetal is formed and extracted into the aldehyde phase, and the aldehyde phase and the water phase are separated to make the acetal and water phase separation.

4. Add 5wt%-10wt% water to the extract phase, and distill under acidic conditions or with a catalyst to decompose the acetal to produce lower polyols and aldehydes. After the aldehydes are distilled out, the decomposition reaction can proceed forward, and low-grade polyol products are obtained, and the aldehydes are recovered at the same time.

5. The aldehydes dissolved in the raffinate phase of the dilute aqueous solution are separated and recovered by distillation or rectification.

The lower polyols include: ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, glycerol, 2,3-butanediol, 1,3-butanediol or 1,4-butanediol and a mixture of two or more thereof.

The beneficial effect of the present invention is that the reaction is completed within 0.5h under suitable conditions, the reaction rate is fast, and it is suitable for continuous production. The de-concentration process has low energy consumption, does not use benzene and other extraction agents, and has low pollution.

Description of drawings

Fig. 1 is a schematic flow chart of a novel reactive extraction process for extracting lower polyols from dilute aqueous solutions.

Detailed ways

The invention provides a novel reactive extraction process for extracting low-level polyols from dilute aqueous solutions with a mass concentration of less than 30 wt%. The reactive extraction process is a novel reactive extraction method in which the reactant and the extractant are the same substance, and will have two or more hydroxyl groups and lower polyols (ethylene glycol, 1, 2-propanediol, 1,3-propanediol, glycerol, 2,3-butanediol, 1,4-butanediol and 1,3-butanediol or a mixture of two or more thereof.) Condensation with aldehydes Aldehydes react to generate cyclic acetals to increase their hydrophobicity. Aldehydes (propionaldehyde, n-butyraldehyde, isobutyraldehyde and isovaleraldehyde) that have a boiling point lower than water and are partially miscible with water are used as reactants It is also used as an extractant, without introducing new solvents, and the process is simple. The boiling point of the selected aldehydes is lower than that of water, so that when distillation or rectification is used to recover aldehydes from the raffinate phase, the aldehydes are obtained from the fractions, and the water phase The impurities in it can be stored in the water phase and separated, which is more important for complex systems containing a large amount of impurities such as fermentation broth. The technological process of the low polyol extracted from dilute aqueous solution is (as shown in Figure 1):

1. Use acid to adjust the pH of the dilute aqueous solution containing lower polyols to be less than 3, or use cation exchange resins, or use catalysts such as solid acids to catalyze the acetal reaction;

2. Add 5wt% to 100wt% propionaldehyde, butyraldehyde, isobutyraldehyde or isovaleraldehyde of the solution to the dilute aqueous solution, so that the aldehydes can form a single phase as an extractant;

3. After the aldehydes dissolved in the dilute aqueous solution react with the lower polyols in the reaction extraction tower in Figure 1, the cyclic acetal is formed and extracted into the aldehyde phase, and the aldehyde phase and the water phase are separated to make the acetal and the water phase separation;

4. Add 5wt%-10wt% water to the extraction phase, and distill under acidic conditions or with a catalyst to decompose the acetal to produce lower polyols and aldehydes. After the aldehydes are distilled off, the decomposition reaction can proceed forward, and the low-grade polyol products can be obtained in the low-grade polyol reduction tower.

5. For the aldehydes dissolved in the raffinate phase of the dilute aqueous solution, the impurities are separated and recovered in the aldehyde recovery tower by distillation or rectification. The method of the present invention will be described below by citing specific examples.

Example 1

(1) Dilute aqueous solution of lower alcohols: 30 mL of 5 wt % 1,3-propanediol aqueous solution,

(2) Extractant: Propionaldehyde 10mL

(3) Reaction conditions: adjust the pH to 1 with hydrochloric acid

(4) Reaction temperature: 15°C

(5) Extraction reaction time: 1h

(6) Results of the extraction reaction: After intermittent stirring, 4 mL of the propionaldehyde phase was obtained, which contained most of the acetal formed.

(7) Decomposition of acetal: separate the extraction phase, put it into a distillation apparatus, add 0.4mL of water and 0.1mL of concentrated hydrochloric acid, heat at 50-100°C, and collect the distillate. After testing, the distillate was 95wt% propionaldehyde, and the residual liquid in the distillation tower was 98wt% 1,3-propanediol.

(8) Recovery of propionaldehyde in the raffinate phase: through detection, the concentration of 1,3-propanediol in the raffinate phase is lower than 0.01%,

The raffinate phase is simply distilled at 50-80°C to obtain 95wt% propionaldehyde.

Example 2

(1) Dilute aqueous solution of lower alcohols: 30 mL of 5 wt % 1,3-propanediol aqueous solution;

(2) Extractant: Propionaldehyde 10mL;

(3) Reaction conditions: 0.1-3g of H-type cation exchange resin;

(4) Reaction temperature: 15°C;

(5) Extraction reaction time: 0.5h;

(6) Results of the extraction reaction: After intermittent stirring, 4 mL of the propionaldehyde phase was obtained, which contained most of the acetal formed.

(7) Decomposition of acetal: separate the extraction phase, put it into a distillation apparatus, add 0.4mL of water, 0.5g of H-type cation exchange resin, heat at 50-100°C, and collect the distillate. After testing, the distillate was 95wt% propionaldehyde, and the residue in the distillation tower was 98wt% 1,3-propanediol.

(8) Recovery of propionaldehyde in the raffinate phase: the raffinate phase is simply distilled at 50-80°C to obtain 95 wt% propionaldehyde.

Example 3

(1) Dilute aqueous solution of lower alcohols: 30 mL of 5 wt % 1,3-propanediol aqueous solution;

(2) Extractant: n-butyraldehyde 10mL;

(3) Reaction conditions: 0.1-3g of H-type cation exchange resin;

(4) Reaction temperature: 15°C;

(5) Extraction reaction time: 0.5h;

(6) Extraction reaction result: After intermittent stirring, 6 mL of n-butyraldehyde phase was obtained, which contained most of the acetal formed.

(7) Decomposition of acetal: separate the extraction phase, put it into a distillation apparatus, add 0.5mL of water, 0.5g of H-type cation exchange resin, heat at 50-100°C, and collect the distillate. After testing, the distillate was 95wt% n-butyraldehyde, and the residual liquid in the distillation tower was 98wt% 1,3-propanediol.

(8) Recovery of n-butyraldehyde in the raffinate phase: through testing, the concentration of 1,3-propanediol in the raffinate phase is lower than 0.01%, and the raffinate phase is simply distilled at 50-80° C. to obtain 95% n-butyraldehyde.

Example 4

(1) Dilute aqueous solution of lower alcohols: 30 mL of 5 wt % 1,3-propanediol aqueous solution;

(2) Extractant: isobutyraldehyde 10mL;

(3) Reaction conditions: 0.1-3g of H-type cation exchange resin;

(4) Reaction temperature: 15°C;

(5) Extraction reaction time: 0.5h;

(6) Results of extraction reaction: After intermittent stirring, 6 mL of isobutyraldehyde phase was obtained, which contained most of the acetal formed.

(7) Decomposition of acetal: separate the extraction phase, put it into a distillation apparatus, add 0.5mL of water, 0.5g of H-type cation exchange resin, heat at 50-100°C, and collect the distillate. After testing, the distillate was 95% by weight of isobutyraldehyde, and the residual liquid in the bottom of the distillation tower was 98% of 1,3-propanediol.

(8) Recovery of isobutyraldehyde in the raffinate phase: through testing, the concentration of 1,3-propanediol in the raffinate phase is lower than 0.01%, and the raffinate phase is simply distilled at 50-80°C to obtain 95wt% isobutyraldehyde.

Example 5

(1) Dilute aqueous solution of lower alcohols: 30 mL of mixed fermentation broth of 5wt% 1,3-propanediol+2wt% 2,3-butanediol+3wt% glycerol;

(2) Extractant: Propionaldehyde 20mL;

(3) Reaction conditions: 0.1-3g of H-type cation exchange resin;

(4) Reaction temperature: 15°C;

(5) Extraction reaction time: 1h;

(6) Results of the extraction reaction: After intermittent stirring, 10 mL of the aldehyde phase was obtained, which contained most of the acetal formed.

(7) Decomposition of acetal: separate the extraction phase, put it into a distillation apparatus, add 1mL of water, 0.5g of H-type cation exchange resin, heat at 50-100°C, and collect the distillate. After testing, the distillate is 95wt% propionaldehyde, and the bottom liquid of the distillation tower is a mixture of 1,3-propanediol, 2,3-butanediol and glycerin.

(8) Recovery of propionaldehyde in the raffinate phase: through detection, the concentrations of 1,3-propanediol, 2,3-butanediol, and glycerol in the raffinate phase are all lower than 0.01wt%, and the raffinate phase is simply distilled at 50-80°C , can recover 95wt% propionaldehyde.

Claims (2)

1. novel reaction extraction process that from dilute aqueous soln, extracts lower polyol, it is characterized in that: described reaction, extraction technology is that reagent and extraction agent are the novel reaction extraction process method of same substance, the described extraction from dilute aqueous soln contained two or more hydroxyls, and carbonatoms smaller or equal to the technological process of 4 lower polyol is:

1) pH that regulates the dilute aqueous soln contain lower polyol with acid is less than 3, or uses the catalyzing cation exchange resin aldolization;

2) 5wt%～100wt% propionic aldehyde, butyraldehyde, isobutyric aldehyde or the isovaleric aldehyde of adding solution in dilute aqueous soln make aldehydes can form a phase separately, as extraction agent;

3) aldehydes and the lower polyol that is dissolved in the dilute aqueous soln, forms cyclic acetal and is extracted into the aldehyde phase after 0.2～24 hour-10～60 ℃ of reactions, and separating aldehyde phase and water make acetal and aqueous phase separation;

4) add the water of 5wt%～10wt% in the extraction phase, at acidic conditions or have under the condition of catalyzer and distill, make acetal decomposition produce lower polyol and aldehydes, make decomposition reaction be able to forward after aldehydes distills out and carry out, obtain the lower polyol product, reclaim aldehydes simultaneously;

5) dissolved aldehydes in the dilute aqueous soln extracting phase, by the distillation or rectifying with its Separation and Recovery.

2. according to the described novel reaction extraction process that from dilute aqueous soln, extracts lower polyol of claim 1, it is characterized in that: described lower polyol comprises: ethylene glycol, 1,2-propylene glycol, 1, ammediol, glycerol, 2,3-butyleneglycol, 1,4-butyleneglycol or 1,3 butylene glycol or its two or more mixture.