A method for processing alcohol mixtures

Abstract

This invention provides a method for processing alcohol mixtures, comprising the following steps: Step A: Dissolving a high-amine-value alcohol mixture containing amino compounds in a first organic solvent to obtain an alcohol mixture solution; Step B: Reacting the alcohol mixture solution obtained in Step A with an organic acid to obtain a reaction mixture solution, wherein the amino compounds contained in the alcohol mixture react with the organic acid to generate an ammonium salt product and a low-amine-value alcohol, wherein R-NH2 is the amino compound, HA is the organic acid, and R-NH3A is the ammonium salt product; Step C: Adding the reaction mixture solution to a second organic solvent, mixing thoroughly, and filtering to obtain a filter cake and a filtrate, wherein the ammonium salt product is insoluble in the second organic solvent and exists in the filter cake, and the low-amine-value alcohol is soluble in the second organic solvent and exists in the filtrate. This invention separates and purifies a high-amine-value alcohol mixture into high-amine-value amino compounds and low-amine-value alcohol components, allowing for the separate utilization of each component with higher value.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a method for processing alcohol mixtures. Background Technology

[0002] Polyurethane is widely used in the market for home furnishings and daily necessities, and end consumers generate a large amount of polyurethane material that needs to be recycled after use. However, during the chemical degradation process of polyurethane materials, a mixture of polyols with high amine values ​​is often produced, which affects subsequent use. If the high-amine-value amino compounds and low-amine-value polyols are separated, high-value amino compounds and low-amine-value polyols can be obtained. However, there is currently no readily available technology to achieve this goal. Summary of the Invention

[0003] The purpose of this invention is to provide a method for processing high-amine-value alcohol mixtures containing the amino compound phenylamino, thereby achieving the separation and purification of the alcohol mixture to extract multiple components for recycling.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A method for processing an alcohol mixture, the alcohol mixture comprising an amino compound and a low-amine-value alcohol, wherein the amine-value alcohol has an amine value of 0–200 mg KOH / g, and the mixture is prepared by perchloric acid-glacial acetic acid titration, automatically titrated using a potentiometric titrator and calculated after analysis. The processing method includes the following steps:

[0006] The viscosity of the alcohol mixture is greater than 30,000 mPa·s.

[0007] Step A: Dissolve the alcohol mixture in the first organic solvent to obtain an alcohol mixture solution;

[0008] Step B: React the alcohol mixture obtained in Step A with an organic acid to obtain a reaction mixture.

[0009] The amino compounds contained in the alcohol mixture react with organic acids as follows:

[0010]

[0011] R-NH2 is an amino compound, HA is an organic acid, and R-NH3A is an ammonium salt product;

[0012] Step C: After mixing the reaction mixture with the second organic solvent, filter to obtain a filter cake and a filtrate. The ammonium salt product is insoluble in the second organic solvent and is present in the filter cake, while the low-amine value alcohol is soluble in the second organic solvent and is present in the filtrate.

[0013] Furthermore, amino compounds include polyols containing both amine and hydroxyl groups.

[0014] Furthermore, the amino compound includes phenylamino compounds, preferably phenylamino alcohols.

[0015] Furthermore, amino compounds include substances containing phenylamino groups.

[0016] Furthermore, the organic acid is a straight-chain carboxylic acid and / or a polycarboxylic acid, and the carboxyl equivalent of the organic acid is not less than the amino equivalent of the alcohol mixture.

[0017] Furthermore, polycarboxylic acids include dicarboxylic acids.

[0018] Furthermore, the carboxyl functionality of the organic acid is not less than 2.

[0019] Furthermore, the first organic solvent is one or a combination of methanol, ethanol or isopropanol.

[0020] Furthermore, the alcohol mixture is a recycled alcohol.

[0021] Furthermore, the recovered alcohol is a product of the degradation of polyurethane waste.

[0022] Furthermore, the second organic solvent is dichloromethane.

[0023] Furthermore, the ratio of the first organic solvent to the second organic solvent by weight is 1:1 to 10.

[0024] Furthermore, the processing methods further include:

[0025] Step D: Evaporate the filtrate obtained in step C to obtain a low-amine-value alcohol component.

[0026] Furthermore, the processing methods further include:

[0027] Step E: Recover amino compounds from the filter cake obtained in Step C.

[0028] Furthermore, step E includes:

[0029] Step E1: Dissolve the filter cake obtained in step C in water and adjust the pH to ≥10 with an alkaline solution. The ammonium salt products in the filter cake react with the alkaline substance to produce amino compounds and organic acid salts.

[0030] Step E2: Extract and separate the product obtained in step E1 to obtain an amino compound;

[0031] Furthermore, in step E1, the alkaline solution is an aqueous solution of NaOH, and the reaction is as follows:

[0032]

[0033] NaA is an organic acid salt.

[0034] Furthermore, in step E2, the product obtained in step E1 is extracted with ethyl acetate, the ethyl acetate phases are combined, and the product is obtained by vacuum distillation to obtain an amino compound with a high amine value.

[0035] Furthermore, step E further includes:

[0036] Step E3: Adjust the aqueous phase after extraction in step E2 with an acidic solution to convert organic acid salts into organic acids and recover them.

[0037] In step E3, the acidic solution is hydrochloric acid, and the reaction is as follows:

[0038] NaA + HCl → HA + NaCl.

[0039] Furthermore, in step B, the reaction temperature is 20–65°C.

[0040] The present invention further claims protection for the low-amine-value alcohol obtained by any of the above-described schemes.

[0041] The present invention further claims protection for amino compounds obtained by any of the above-described schemes.

[0042] This invention provides a convenient method for obtaining low-amine-value recovered alcohols (i.e., low-amine-value alcohol components) while simultaneously separating high-amine-value byproducts (amino compounds). The overall process of this invention is as follows:

[0043] In the first organic solvent, the basicity of the phenylamino group in the recovered alcohol is used to cause the high-amine-value amino compound to undergo an acid-base neutralization reaction with a suitable organic acid under room temperature or heating conditions, thereby generating an ammonium salt product. Due to the difference in solubility between the amino compound in the high-amine-value alcohol and the ammonium salt product and the low-amine-value alcohol in the solvent, the low-amine-value alcohol component can be separated.

[0044] The general formula for acid-base neutralization reactions is:

[0045]

[0046] R-NH2 is an amino compound, and HA is an organic acid. It is an ammonium salt product.

[0047] Because ammonium salt products are highly polar and poorly soluble in the second organic solvent, they can be filtered out, while low-amine alcohols remain in the second organic solvent. Therefore, the two can be separated by filtration.

[0048] After filtration and separation, the filter cake is dissolved in water, and then alkali is added to adjust the pH to alkaline. This means that the ammonium salt products in the filter cake can be reduced to amino compounds and alkali metal organoacids by the alkali solution, as shown in the following reaction:

[0049]

[0050] In this process, NaA represents an organic acid salt. The ammonium salt product is reacted under alkaline conditions to recover the amino compound. Extraction and separation yields an amino compound with a high amine value. This high-amine-value amino compound is a high-value chemical product with a wide range of applications.

[0051] The remaining organic acid salts in the aqueous mixture are adjusted to acidity with hydrochloric acid, meaning that alkali metal organic acid salts can react with strong acids to produce inorganic salts and organic acids, thereby recovering the organic acids. The reaction is as follows:

[0052] NaA + HCl → HA + NaCl

[0053] Then, through extraction and other steps, the organic acids are recovered.

[0054] On the other hand, this invention also claims protection for the low-amine-value alcohol component obtained from steps C and D. Due to the reduction in amine value, the recovered alcohol can meet similar specifications to the virgin alcohol, and its product value is greatly enhanced.

[0055] On the other hand, the present invention also claims protection for amino compounds obtained by step E, including free amines and amino-containing polyols.

[0056] The present invention has the following advantages over the prior art:

[0057] (1) The mixture of high-amine alcohols is separated and purified into high-amine amino compounds and low-amine alcohol components. The two components have higher utilization value. High-amine amine alcohols can be used as curing agents and catalysts, while low-amine alcohol components can be re-involved in the process of manufacturing polyurethane, opening up different sales markets.

[0058] (2) The low-amine-value recovered alcohol obtained can be used in a large proportion to manufacture polyurethane, thereby increasing the utilization rate of polyurethane solid waste, improving production efficiency, and meeting market demand.

[0059] (3) The reaction conditions are mild and the production cost is low;

[0060] (4) The first organic solvent, the second organic solvent, organic acid and ethyl acetate involved can all be recycled and reused, reducing the cost of the process.

[0061] (5) No amide groups are generated in the reaction products to avoid poor compatibility between amide groups and alcohols, phase separation and precipitation, resulting in insufficient product uniformity. Attached Figure Description

[0062] The above description of the present invention and the following detailed embodiments will be better understood when read in conjunction with the accompanying drawings. It should be noted that the drawings are merely examples of the claimed technical solutions.

[0063] Figure 1 This is the infrared spectrum of CJ-3-56 of Comparative Example 1 of this invention. Detailed Implementation

[0064] The following detailed description of the features and advantages of the present invention is sufficient to enable any person skilled in the art to understand the technical content of the present invention and implement it accordingly. Furthermore, based on the specification, claims and drawings disclosed herein, those skilled in the art can easily understand the related objects and advantages of the present invention.

[0065] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below.

[0066] The detailed features and advantages of this patent are described below in the specific embodiments. The content is sufficient to enable any person skilled in the art to understand the technical content of this patent and implement it accordingly. Furthermore, based on the specification and claims disclosed in this specification, a person skilled in the art can easily understand the related objectives and advantages of this patent.

[0067] To make the purpose, technical solution and advantages of this patent clearer, the implementation method of this patent will be described in further detail below.

[0068] The raw materials used in this embodiment are commercially available. Diphenylmethane diisocyanate (PMDI): trade name 44V20L, purchased from Covestro; polyol NJ-303, purchased from Jurong Ningwu New Materials Co., Ltd.

[0069] Test Example 1

[0070] The amine value test method used in this invention is: amine value is determined by potentiometric titration.

[0071] The amine value is the number of milligrams of potassium hydroxide required to neutralize one gram of basic amine. The amine value is commonly used to indicate the functionality of polyols. This experiment uses the perchloric acid-glacial acetic acid titration method, with automatic titration performed using a potentiometric titrator, and the amine value of the sample calculated after analysis.

[0072] 1. Prepare reagents and instruments

[0073] Sample: Hydroxyl-containing compound (i.e., modified polyurethane)

[0074] Titrant: 0.1 mol / L perchloric acid-glacial acetic acid standard solution

[0075] Solvents: glacial acetic acid and acetonitrile

[0076] Instruments: Lei magnetic potential titrator (model ZDJ-4B), titration stirring table, non-aqueous electrode (filled with ethanol-saturated lithium chloride), 4.100mL titration cup, electronic balance (accurate to 0.1mg), beaker, graduated cylinder, volumetric flask, etc.

[0077] 2. Measurement Method

[0078] Weigh approximately 0.2 g of the sample and dissolve it in 20 mL of glacial acetic acid. Then add 20 mL of acetonitrile to dilute the solution. After stirring until the sample dissolves, transfer the solution to a titration cup and place it on the titration stage. Set the instrument titration method according to the following parameters and perform titration analysis using a 0.1 mol / L standard perchloric acid-acetic acid solution. Obtain the results after the analysis is completed.

[0079] The parameters of the titrator are as follows:

[0080] Endpoint mode: Differential determination;

[0081] Endpoint volume determination: 5 units before; 0.3 units after.

[0082] Minimum dropping volume: 10 μL;

[0083] Maximum dropping volume: 1000uL;

[0084] Endpoint determination differential value: 200;

[0085] Pre-titration: None;

[0086] Stirring speed: 200;

[0087] Interval between drops: 2000 m / s;

[0088] The formula for calculating the amine value is: Amine value = C * V * 56.11 / m

[0089] Where: V—titer endpoint volume (ml); C—concentration of perchloric acid-glacial acetic acid standard solution (mol / L); m—sample amount (g); 56.11—molar mass of potassium hydroxide (g / mol).

[0090] Test Example 2

[0091] The method used in this invention for testing hydroxyl values ​​is ASTM E1899-2016.

[0092] Test Example 3

[0093] The infrared spectroscopy analysis methods used in this invention are all in accordance with the General Rules for Infrared Spectroscopy Analysis GB / T 6040.

[0094] Comparative Example 1

[0095] Step 1: Prepare 400g of ethylene glycol as a degradation agent;

[0096] Step 2: First, heat the degradation agent to 190°C under nitrogen protection, then add 80g of polyurethane rigid foam waste powder from the polyurethane refrigerator insulation layer into the degradation agent and stir for 12 hours for alcoholysis.

[0097] Step 3: While still hot, filter the mixed solution using rapid filter paper with a pore size of 20 μm. Distill the filtrate under reduced pressure to obtain 81 g of the modified polyurethane CJ-3-56, which is used as an intermediate for the modified resin or as the modified resin. The recovered alcohol solution is then dissolved in methanol and filtered through rapid filter paper. The filter cake is then distilled under reduced pressure until no fraction appears. After drying, it is weighed to obtain 16 g. The initial polyurethane content in the modified polyurethane is (80-16) / 81 = 79%. The tested amine value is 255 mg KOH / g; the tested hydroxyl value is 540 mg KOH / g; and the viscosity is greater than 30000 mPa.

[0098] The infrared spectrum of modified polyurethane CJ-3-56 was measured according to the general rules of infrared spectroscopy analysis GB / T 6040, as shown below. Figure 1 As shown, it can be found at 1680cm -1 ~1780cm -1 1706 cm in the wavenumber range -1 The presence of an infrared absorption peak with an intensity of only about 0.05 indicates that the content of urethane bonds is already low, and most of the urethane groups have been degraded into amino compounds.

[0099] Step 4: The modified polyurethane resin obtained in step 3 is mixed with PMDI at a weight ratio of 1:1. The reaction begins to exotherm within 5 seconds, making it impossible to prepare a uniformly cured polyurethane.

[0100] Step 5: Mix the filter cake obtained in Step 3 with an equal weight of N3O3 to form Component B, with an amine value of 130 mg KOH / g. Then mix it with curing agent PMDI at a weight ratio of B:curing agent = 1:0.75. The reaction begins to exotherm within 30 seconds, making it impossible to prepare a uniformly cured polyurethane. It can only become hazardous waste or requires further processing and modification before it can be used, increasing the production process and production costs.

[0101] As can be seen from Comparative Example 1, the high amine value polyol mixture CJ-3-56 is difficult to apply due to its excessively high amine value.

[0102] Example 1

[0103] Step 1: Dissolution. Take 30g of the recovered polyol CJ-3-56 obtained from Comparative Example 1 and add it to 100mL of methanol (the first organic solvent). Stir at room temperature (25℃) until completely dissolved.

[0104] Step 2: Add organic acid to react with phenylamino compound. Add 12.5g of oxalic acid (at least the amino equivalent) to the solution obtained in Step 1, and stir at room temperature for 1 hour to allow the oxalic acid to react fully with the phenylamino compound, obtaining a reaction mixture containing ammonium salt product and low-amine-value polyol component.

[0105] Step 3: Extraction and separation of low-amine polyols. The reaction mixture obtained in Step 2 is added to dichloromethane in excess of the methanol solvent from Step 1. 500 mL of dichloromethane can be used, forming a second organic solvent. After stirring for 10 min, the mixture is filtered through rapid filter paper (20 μm pore size), yielding a filter cake containing ammonium salt products and a filtrate containing fewer amino compounds. The filter cake contains ammonium salt products, and the filtrate contains low-amine polyol components (i.e., low-amine alcohols). The filtrate is then rotary evaporated to dryness, yielding 15 g of purified low-amine polyol components with an amine value of 54 mg KOH / g and dichloromethane, as shown in Table 2. The dichloromethane can be collected using a condenser and reused.

[0106] Step 4: Recovery of the amino compound. After thoroughly drying the filter cake obtained in Step 3, dissolve it in 100 mL of water, adjust the pH to greater than 10 with 40% NaOH aqueous solution, then mix thoroughly with ethyl acetate three times the volume of water and pour into a separatory funnel for extraction (100 mL * 3). Collect the oil phase, i.e., the ethyl acetate phase. Combine the ethyl acetate phases, mix thoroughly, and distill under reduced pressure. Recover the ethyl acetate through a condenser to obtain 14.5 g of a high-amine-value amino compound with an amine value of 441 mg KOH / g.

[0107] Table 2: Reaction conditions and detection results of alcohol mixtures

[0108]

[0109] Example 2

[0110] The difference between this embodiment and Example 1 is that isopropanol is used as the first organic solvent to obtain 14g of a low-amine polyol with an amine value of 59mgKOH / g and 15g of a high-amine amino compound.

[0111] Comparative Example 2

[0112] The difference between this comparative example and Example 1 is that p-toluenesulfonic acid with an equal carboxyl equivalent was used instead of oxalic acid in the reaction. As a result, it was found that the reaction product did not produce a filter cake when filtered, and the separation effect could not be achieved.

[0113] This indicates that monofunctional organic acids cannot achieve the separation effect; organic acids with a functionality of not less than 2 are required to achieve the separation effect.

[0114] The terminology and expressions used herein are for descriptive purposes only, and the invention should not be limited to these terms and expressions. The use of these terms and expressions does not imply the exclusion of any illustrative and descriptive equivalents (or parts thereof), and it should be recognized that various modifications that may exist should also be included within the scope of the claims. Other modifications, variations, and substitutions may also exist. Accordingly, the claims should be considered to cover all such equivalents.

[0115] Similarly, it should be noted that although the present invention has been described with reference to the specific embodiments described above, those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and various equivalent changes or substitutions can be made without departing from the spirit of the present invention. Therefore, any changes or modifications to the above embodiments within the scope of the essential spirit of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A method for treating an alcohol mixture comprising an amino compound and a low amine number alcohol, characterized in that, The low amine value alcohol has an amine value of 0-200 mgKOH / g, the alcohol mixture is a recycled alcohol obtained from hard polyurethane foam waste and ethylene glycol degradation reaction, and the alcohol mixture has a viscosity greater than 30000 mPa.s, The treatment method comprises the following steps: Step A: dissolving the alcohol mixture in a first organic solvent, stirring at room temperature until completely dissolved to obtain an alcohol mixture, and the first organic solvent is one or a combination of more than one selected from methanol, ethanol or isopropanol; Step B: reacting the alcohol mixture obtained in step A with an organic acid to obtain a reaction mixture, and the reaction is as follows: ； wherein R-NH2 is the amino compound; HA is the organic acid, and the organic acid is oxalic acid, and R-NH3A is an ammonium salt product; Step C: adding the reaction mixture to dichloromethane and mixing uniformly, then filtering to obtain a filter cake and a filtrate, and the specific gravity of the first organic solvent to the dichloromethane is 1:1-10 by weight, the ammonium salt product is difficult to dissolve in the dichloromethane, and the low amine value alcohol is dissolved in the dichloromethane; Step D: evaporating the filtrate obtained in step C to obtain the low amine value alcohol component; Step E1: dissolving the filter cake obtained in step C in water, and adjusting the pH to be greater than or equal to 10 with an alkaline solution, and the ammonium salt product in the filter cake reacts with the alkaline substance to produce the amino compound and an organic acid salt; The alkaline solution is an aqueous NaOH solution, and the reaction is as follows: ； wherein NaA is an organic acid salt; Step E2: extracting the product obtained in step E1 with ethyl acetate, combining the ethyl acetate phase, and distilling under reduced pressure to obtain the amino compound; Step E3: adjusting the water phase after extraction in step E2 with hydrochloric acid to convert the organic acid salt to the organic acid and recover it, and the reaction is as follows: 。

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