Organic acid ester deacidification agent and deacidification method

Abstract

Embodiments of the present invention disclose an organic acid ester deacidification agent and a deacidification method. The deacidification agent of the present invention is either or both of Ca(OH)2 and CaO. The deacidification agent provided by the present invention is widely available and inexpensive. The deacidification agent is used for deacidification of organic acid esters and has the advantages of good deacidification effect, simple operation, environmentally friendly process, and high product yield. Furthermore, the discharged residue can be recycled as a desulfurizer in power plants, thus having good application prospects.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of fine chemicals, and in particular to an organic acid ester deacidification agent and a deacidification method. Background Art

[0002] Organic acid esters produced in fine chemical processes primarily include monobasic acid esters, dibasic acid esters, polybasic acid esters, carbonates, sulfonates, and sulfites, which are widely used as solvents and synthetic raw materials. Organic acid esters are often synthesized through an esterification reaction between an organic acid and an alcohol in the presence of an acidic catalyst. Due to thermodynamic equilibrium constraints, incompletely reacted organic acid is unavoidable during the reaction. Furthermore, raw materials from the previous process often contain acidic substances such as humic acid, tar acid, HNO3, and H2O2. The acid value of the crude product typically ranges from 1 to 30 mg KOH / g, and the presence of trace amounts of acidic substances can seriously affect product quality.

[0003] Patent CN101049550A discloses a solid alkaline adsorbent for deacidification of liquid organic acid esters. The preparation steps of this adsorbent include molding, drying, and roasting, which is a complex process and limits its industrial application. Patent CN111389344A discloses an adsorbent for deacidification and dehydration of ester compounds. This adsorbent is made from γ-Al2O3, a binder, a pore-forming agent, MgO, etc., and is prepared through grinding, extrusion molding, and roasting. The entire process is complex and costly. Patent CN105566117A discloses a method for deacidification of isooctyl nitrate using a saturated sodium chloride solution of sodium hydroxide. This method has the disadvantages of large amount of deacidifying agent, low product yield, and large amount of high-salt wastewater discharge. Patent CN109135920A discloses a method for removing acid value from oils and fats using neutral or basic aluminum oxide as an adsorbent. This method has the disadvantages of large amount of adsorbent, long time consumption, and the need for vacuuming during the removal process, which generates solid waste. Summary of the Invention

[0004] To this end, an embodiment of the present invention provides an organic acid ester deacidification agent and a deacidification method. The deacidification agent is Ca(OH)2 or CaO or a mixture of the two, which is widely available and inexpensive. The deacidification agent is used for the deacidification of organic acid esters and has the advantages of good deacidification effect, simple operation, green process, and high product yield. The discharged residue can be recycled as a desulfurizer in power plants, and has good application prospects.

[0005] In order to achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] According to a first aspect of an embodiment of the present invention, the present invention provides an organic acid ester deacidification agent, wherein the deacidification agent is any one or both of Ca(OH)2 and CaO.

[0007] Furthermore, when the deacidifying agent is composed of Ca(OH)2 and CaO, the mass ratio of Ca(OH)2 to CaO is (1-5):1.

[0008] Furthermore, the particle size of the deacidifying agent is 120-600 mesh, preferably 200-400 mesh.

[0009] According to a second aspect of the embodiments of the present invention, the present invention provides use of the deacidification agent as described in any one of the above items in the deacidification of organic acid esters.

[0010] According to a third aspect of the embodiments of the present invention, the present invention provides a method for deacidification of an organic acid ester, wherein the deacidification agent as described in any one of the above items is used to perform single-stage or multi-stage deacidification on the organic acid ester.

[0011] Furthermore, the single-stage deacidification comprises: mixing an organic acid ester with a deacidifying agent, and performing solid-liquid separation to obtain a deacidified product;

[0012] The mass ratio of the organic acid ester to the deacidifying agent is 100:(0.2-2); the mixing conditions are: room temperature-80°C, 2-60 minutes, preferably 40-60°C, 2-20 minutes; the solid-liquid separation conditions are: 1500-2000rpm, 5-20 minutes.

[0013] Furthermore, the multi-stage deacidification includes: mixing the organic acid ester with the deacidification agent, solid-liquid separation, completing single-stage deacidification, and repeating the deacidification process of mixing with the deacidification agent and solid-liquid separation to obtain a deacidified product;

[0014] In each stage of deacidification, the mass ratio of organic acid ester to deacidifying agent is 100:(0.1-1); the mixing conditions are: room temperature-80°C, 2-30 minutes, preferably 40-60°C, 2-10 minutes; the solid-liquid separation conditions are: 1500-2000rpm, 5-10 minutes;

[0015] The multi-stage deacidification includes secondary deacidification or tertiary deacidification.

[0016] Furthermore, the method comprises the following steps:

[0017] (1) feeding the organic acid ester and the deacidifying agent into a first powder suction mixing system and a first horizontal screw centrifuge in sequence to obtain a liquid phase and a residue;

[0018] (2) The liquid phase and the deacidifying agent are sequentially fed into a second powder suction mixing system and a second horizontal screw centrifuge to obtain an ester product and a residue.

[0019] Furthermore, the method further comprises: using the residues from step (1) and step (2) as a desulfurizing agent for desulfurization in a power plant.

[0020] Furthermore, the organic acid ester includes monobasic acid ester, dibasic acid ester, tribasic acid ester, preferably dimethyl dibasic acid ester, diethyl dibasic acid ester, mixed dimethyl dibasic acid ester, triacetin, geranyl acetate, isopropyl myristate, soybean oil, fish oil, olive oil, peanut oil, sunflower oil.

[0021] The embodiments of the present invention have the following advantages:

[0022] The deacidification method provided by the present invention can remove the acidic substance concentration in the organic acid ester to meet the product requirements (the acid value requirement of the product is usually 0.2-0.4 mg NaOH / g product), and can also absorb trace moisture in the product to reduce the moisture content. In addition, during the deacidification process, by controlling the residence time of the deacidification agent in the liquid phase, the temperature of the deacidification process and other parameters, the solubility of the deacidification agent in the liquid phase is reduced, so that the total metal ion content (including calcium ions from the deacidification agent) in the deacidified product also meets the requirements, and the ignition residue content is less than 10 ppm (i.e., 0.001%). The present invention adopts a method of mixing the deacidification agent and the organic acid ester solid-liquid for a certain period of time and then high-speed centrifuging to ensure that the deacidified product is clear and transparent, and no solid deacidification agent powder remains. The deacidification method of the present invention is not only suitable for the deacidification of synthetic organic acid esters, but also for the deacidification of oils and fats, such as soybean oil, fish oil, olive oil, peanut oil, sunflower oil, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other implementation drawings based on the provided drawings without inventive effort.

[0024] Figure 1 A schematic diagram of a deacidification process for an organic acid ester provided in Example 1 of the present invention;

[0025] Among them, S-1: first powder suction and mixing system; S-2: second powder suction and mixing system; C-1: first horizontal screw centrifuge; C-2: second horizontal screw centrifuge. DETAILED DESCRIPTION

[0026] The following describes the implementation of the present invention using specific embodiments. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. Obviously, the embodiments described are only a portion of the present invention, not all of it. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0027] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.

[0028] Example 1

[0029] This embodiment provides a method for deacidification of organic acid esters:

[0030] (1) 0.2 g of Ca(OH)2 powder (300 mesh) was mixed with 20 g of crude mixed dimethyl ester (i.e., a mixture of dimethyl succinate, dimethyl glutarate, and dimethyl adipate, industrially known as DBE oil, with a water content of 0.5 wt% and an acid value of 20.0 mg NaOH / g oil), stirred at 40°C for 10 min, and centrifuged at 1800 rpm for 10 min to obtain a liquid phase and a solid phase;

[0031] (2) 0.05 g of Ca(OH)2 was added to the liquid phase obtained in step (1), and the mixture was stirred at 40°C for 10 min, followed by centrifugation at 1800 rpm for 5 min to obtain a liquid deacidification product and a solid phase, and the deacidification product was analyzed.

[0032] Result analysis: Under the conditions of primary deacidification agent dosage of 0.2 / 20=1% and secondary deacidification dosage of 0.05 / 20=0.25%, the acid value of the deacidified product was 0.3mg NaOH / g product, the dehydration rate was 70%, the product yield was 96.0%, and the ignition residue content was 6ppm.

[0033] Examples 2 to 18

[0034] The organic acid esters treated in Examples 2 to 18 were DBE oil (same as in Example 1). The difference from Example 1 was the deacidification conditions, such as the composition and amount of the deacidifying agent, the mixing temperature and time, the deacidification stage, etc. Other conditions remained unchanged. The results are shown in Table 1 below.

[0035] Table 1 Deacidification examples and results of DBE oil

[0036]

[0037]

[0038] Note: The dosage of deacidifying agent refers to the mass ratio of deacidifying agent to raw material ester (DBE oil).

[0039] Examples 19 to 28

[0040] The deacidification methods of Examples 19 to 28 differ from those of Example 1 in that the deacidification conditions are different, such as the type of raw ester, the composition and dosage of the deacidification agent. The deacidification temperature of each stage is fixed at 60°C and the deacidification time of each stage is 5 minutes. Other conditions remain unchanged. The results are shown in Table 2 below.

[0041] Table 2 Deacidification examples and results of different organic acid esters

[0042]

[0043]

[0044] Note: The dosage of deacidifying agent refers to the mass ratio of deacidifying agent to raw material ester.

[0045] Example 29

[0046] 500 kg / h of crude mixed dimethyl ester (DBE oil, acid value 25 mg NaOH / g, water content 0.6%, temperature 60°C) and 5 kg / h of Ca(OH)2 / CaO (mass ratio 4:1) powder (300 mesh) were fed into the Figure 1 The first powder was drawn into the mixing system S-1, where it remained for 4 minutes before entering the first decanter centrifuge C-1 (2000 rpm, 10 minutes) to complete primary deacidification. The resulting liquid phase was then fed into the second powder drawing and mixing system S-2 at 500 kg / h and 3.0 kg / h of Ca(OH)2 / CaO (mass ratio 4:1) powder (300 mesh). The mixture remained for 4 minutes before entering the second decanter centrifuge C-2 (2000 rpm, 6 minutes) to complete secondary deacidification, yielding a liquid deacidified product. The deacidified product was analyzed.

[0047] Result analysis:

[0048] The acid value of the product is 0.2 mg NaOH / g product, the dehydration rate is 81%, the yield is 96.2%, and the ignition residue content is 5 ppm.

[0049] Example 30

[0050] 1000 kg / h of crude diisopropyl adipate (acid value 5.0 mg NaOH / g, water content 0.4%, temperature 60°C) and 5.0 kg / h of Ca(OH)2 powder (300 mesh) were continuously fed into the reactor. Figure 1The first powder was drawn into the mixing system S-1, where it remained for 5 minutes before entering the first decanter centrifuge C-1 (2000 rpm, 15 minutes) to complete primary deacidification. The resulting liquid phase was continuously fed into the second powder drawn into the mixing system S-2 at 1000 kg / h and 3.0 kg / h of Ca(OH)2 powder (300 mesh), where it remained for 4 minutes before entering the second decanter centrifuge C-2 (1800 rpm, 10 minutes) to complete secondary deacidification and obtain a liquid deacidified product. The deacidified product was analyzed.

[0051] Result analysis:

[0052] The acid value of the product is 0.2 mg NaOH / g product, the dehydration rate is 75%, the yield is 97.5%, and the ignition residue content is 5 ppm.

[0053] Example 31

[0054] The solid phase Ca(OH)2 residue obtained by separation in the first decanter centrifuge C-1 and the second decanter centrifuge C-2 in Example 30 was collected, water was added, and a suspension with a solid content of 50 g / L was prepared. The suspension was sent to a slurry bed desulfurization tower to simulate the flue gas (temperature 120°C, SO2 content 3000 mg / m 3 Keeping the same conditions, a parallel experiment was conducted using a suspension of pure Ca(OH)2 with the same solid content as the desulfurizer.

[0055] Comparison results show that the desulfurization efficiency of Ca(OH)2 residue as a desulfurizer was 98%, and no VOCs were detected in the exhaust gas after desulfurization. Pure Ca(OH)2 achieved a slightly lower desulfurization efficiency of 96%, demonstrating that the solid phase residue after desulfurization of organic acid esters, due to the presence of the organic acid calcium salt acting as an activator, significantly enhances the SO2 reaction rate and completion.

[0056] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made thereto. Therefore, such modifications and improvements, without departing from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A method for deacidification of an organic acid ester, characterized in that: The method comprises the following steps: (1) feeding the organic acid ester and the deacidifying agent into a first powder suction mixing system and a first horizontal screw centrifuge in sequence to obtain a liquid phase and a residue; (2) the liquid phase and the deacidifying agent are sequentially fed into a second powder suction mixing system and a second horizontal screw centrifuge to obtain an ester product and a residue; The deacidifying agent is CaO, or Ca(OH)2 and CaO in a mass ratio of (1-4):1; The method further comprises: using the residues from step (1) and step (2) for activation and desulfurization of tail gas from a power plant.

2. The method for deacidification of organic acid ester according to claim 1, wherein The mass ratio of the organic acid ester in step (1) or the liquid phase in step (2) to the deacidifying agent is 100:(0.1-1); the mixing conditions are: room temperature-80°C, 2-30 minutes; the solid-liquid separation conditions are: 1500-2000 rpm, 5-10 minutes.

3. The deacidification method of organic acid ester according to claim 2, characterized in that: The mixing conditions are: 40-60°C, 2-10 minutes.

4. The method for deacidification of organic acid ester according to claim 1, wherein The particle size of the deacidifying agent is 120-600 meshes.

5. The method for deacidification of organic acid ester according to claim 1, characterized in that: The organic acid esters include monobasic acid esters, dibasic acid esters, and tribasic acid esters.

6. The method for deacidification of organic acid ester according to claim 5, characterized in that: The organic acid ester is dimethyl dibasic acid ester, diethyl dibasic acid ester, mixed dimethyl dibasic acid ester, triacetin, geranyl acetate, isopropyl myristate, soybean oil, fish oil, olive oil, peanut oil, and sunflower oil.

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