A process for the preparation of 98% pentaerythritol co-producing 99% pentaerythritol

Abstract

The application provides a preparation method of 98% pentaerythritol co-production 99% pentaerythritol, relates to the technical field of basic chemicals, and realizes the preparation of 98% pentaerythritol co-production 99% pentaerythritol by using pentaerythritol crude, hydrolysis under high temperature and high pressure with methyl sulfonic acid as a catalyst and decolorization with activated carbon, so that the preparation method has the characteristics of low cost, low loss and excellent product quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of basic chemical technology, in particular to a preparation method of 98% pentaerythritol co-production of 99% pentaerythritol. BACKGROUND

[0002] Pentaerythritol (PE) is a white powder crystal, which is easily esterified by general organic acids, and is widely used in the production of alkyd resin, synthetic high-grade lubricant, plasticizer, surfactant, medicine and explosive in the coating industry, and is an important chemical raw material. At present, the production of pentaerythritol in industry mainly adopts "sodium method", that is, pentaerythritol is prepared by condensation reaction of formaldehyde and acetaldehyde in the presence of sodium hydroxide alkaline catalyst, and sodium formate is also generated. This method synthesizes pentaerythritol in two steps, the first step is Alder reaction which is an endothermic reaction, and the second step is Cannizzaro reaction which is an exothermic reaction. The condensation process requires a gentle temperature rise, otherwise side reactions will occur, the by-product will increase, the product yield will be reduced, and the difficulty of subsequent separation process will be increased, which will affect the yield and quality of pentaerythritol.

[0003] Over the years, there are many methods for preparing pentaerythritol from formaldehyde and acetaldehyde as raw materials, such as CN105111047A and CN109438182A, which report that the condensation reaction is carried out under the catalysis of liquid alkali. However, during the condensation reaction, by-products such as pentaerythritol formaldehyde, methanol-pentaerythritol acetal and pentaerythritol methyl ether are generated, the content of pentaerythritol is low, and the product quality is affected. CN103044199A reports that 95% pentaerythritol is hydrolyzed to 98% pentaerythritol by using phosphoric acid as catalyst under high temperature and high pressure, but the pentaerythritol needs to be treated in advance before hydrolysis, therefore, the process design is continuous feeding and discharging, and a hydrolysis tower is used as the core reactor, which needs a large amount of water washing and increases the production cost.

[0004] In view of the problems existing in the prior art, it is necessary to find a preparation method of 98% pentaerythritol co-production of 99% pentaerythritol with excellent product quality, low cost and less loss. SUMMARY

[0005] In view of the problems existing in the prior art, the present application provides a preparation method of 98% pentaerythritol co-production of 99% pentaerythritol, which can achieve the purpose of simultaneous production of 98% and 99% pentaerythritol under the condition of impure raw materials and low acidity.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] The present application provides a preparation method of 98% pentaerythritol co-production of 99% pentaerythritol, which comprises the following steps:

[0008] (1), mixing water and crude pentaerythritol, adjusting pH to obtain pentaerythritol solution one, and then hydrolyzing under elevated temperature and pressure to obtain hydrolyzate one;

[0009] (2), decolorizing, filter-pressing, crystallizing and filter-pressing again the hydrolyzate one obtained in step (1) to obtain crystal one and filtrate one, and drying the crystal one to obtain 98% pentaerythritol;

[0010] (3), mixing the crystal one obtained in step (2) and crude pentaerythritol, adjusting pH to obtain pentaerythritol solution two, and then hydrolyzing under elevated temperature and pressure to obtain hydrolyzate two;

[0011] (4), decolorizing, filter-pressing, crystallizing and filter-pressing again the hydrolyzate two obtained in step (3) to obtain crystal two and filtrate two;

[0012] (5), drying the crystal two obtained in step (4) to obtain 99% pentaerythritol.

[0013] Further, the 98% pentaerythritol specifically refers to pentaerythritol with a mass fraction of about 98%, and the 99% pentaerythritol specifically refers to pentaerythritol with a mass fraction of about 99%.

[0014] Further, the crude pentaerythritol in step (1) comprises monopentaerythritol 85-90%, dipentaerythritol 3-5%, tri-pentaerythritol 0.5-1% and the balance of water.

[0015] Further, the pH of the pentaerythritol solution one in step (1) is 2-2.5, and the pH of the pentaerythritol solution two in step (3) is 2.5-3.

[0016] Further, the weight ratio of water to crude pentaerythritol in step (1) is 3-5:1, and preferably 3:1.

[0017] Further, the temperature for the elevated temperature in steps (1) and (3) is 110-140℃, and the time is 3-6h; the pressure for the hydrolysis under elevated pressure is 0.1-0.3Mpa; the decolorization conditions in steps (2) and (4) are: temperature 90-110℃, time 15min, and normal pressure; the crystallization temperature in steps (2) and (4) is 30-50℃, and the time is 3-6h.

[0018] Further, the decolorization in steps (2) and (4) is specifically carried out by adding activated carbon, and the particle size is 100-200 mesh; the addition amount of activated carbon in step (2) is 1.0-2.0% of the total weight of the crude pentaerythritol, and the addition amount of activated carbon in step (2) is 2.0-4.0% of the total weight of the crude pentaerythritol.

[0019] Further, the activated carbon comprises coconut shell powder activated carbon and / or wood powder activated carbon.

[0020] Further, when the stirring rate in step (4) is 5-10 r / min, the crystal size is 40-80 mesh; when the stirring rate is 10-20 r / min, the crystal size is 80-100 mesh; and when the stirring rate is 20 r / min or more, the crystal size is 100-200 mesh.

[0021] Further, the filtrate one in step (2) and the filtrate two in step (4) are both returned to the preparation process of the pentaerythritol solution one in step (1) and / or the preparation process of the pentaerythritol solution two in step (3) to replace water.

[0022] Further, the weight ratio of the filtrate two, the crystal one and the pentaerythritol crude in step (3) is 5-7:1:1, preferably 6:1:1.

[0023] In some specific embodiments, the preparation method of the 98% pentaerythritol co-produced with 99% pentaerythritol comprises the following steps:

[0024] (1) mixing water and pentaerythritol crude, adjusting pH to obtain a pentaerythritol solution one, and then hydrolyzing under heating and pressurization to obtain a hydrolyzed material one;

[0025] (2) decolorizing, pressure filtering, crystallizing and again pressure filtering the hydrolyzed material one obtained in step (1) to obtain a crystal one and a filtrate one, and drying the crystal one to obtain 98% pentaerythritol; wherein the filtrate one is recycled and returned to step (1) to be mixed with water and pentaerythritol crude;

[0026] (3) mixing the crystal one obtained in step (2) and pentaerythritol crude, adjusting pH to obtain a pentaerythritol solution two, and then hydrolyzing under heating and pressurization to obtain a hydrolyzed material two;

[0027] (4) decolorizing, pressure filtering, crystallizing and again pressure filtering the hydrolyzed material two obtained in step (3) to obtain a crystal two and a filtrate two; wherein the filtrate two is recycled and returned to step (3) to be mixed with the crystal one and pentaerythritol crude;

[0028] (5) drying the crystal two obtained in step (4) to obtain 99% pentaerythritol.

[0029] In some specific embodiments, the preparation method of the 98% pentaerythritol co-produced with 99% pentaerythritol comprises the following steps:

[0030] S1: the filtrate one is mixed with the crude pentaerythritol, then is put into a dissolving kettle, then methyl sulfonic acid is added to adjust the pH of the solution, a pentaerythritol solution one is configured, is hydrolyzed under heating and pressurization, and a hydrolyzate one is obtained;

[0031] S2: activated carbon is added to the hydrolyzate one, is decolorized under normal pressure, is filtered under pressure, and carbon residue and colored impurities are removed, the mother liquor is cooled again, is stirred, is crystallized, is filtered under pressure, and a crystal one and a filtrate one are obtained, wherein the filtrate one is returned to the first step for use next time; the crystal one is dried, and 98% pentaerythritol can be obtained;

[0032] S3: the filtrate two is mixed with the obtained crystal one and the crude pentaerythritol, then is put into a dissolving kettle, then methyl sulfonic acid is added to adjust the pH of the solution, a pentaerythritol solution two is configured, is hydrolyzed under heating and pressurization, and a hydrolyzate two is obtained;

[0033] S4: activated carbon is added to the hydrolyzate two, is decolorized under normal pressure, is filtered under pressure, and carbon residue and colored impurities are removed, the mother liquor is cooled again, is stirred, is crystallized, is filtered under pressure, and the filtrate two and a crystal two are obtained, wherein the filtrate two is returned to the step S1 for use next time;

[0034] S5: the obtained crystal two is dried, and 99% pentaerythritol finished product is obtained.

[0035] The technical effects achieved by the present application are as follows:

[0036] 1. In the industry, it is extremely difficult to improve the yield of pentaerythritol to close to 100%, such as more than 98%. The pressurized hydrolysis method using methyl sulfonic acid in the present application can break the chemical bonds such as ether bonds under the conditions of acidity, high temperature and high pressure according to the chemical properties of ethers, acetals and the like, so that poly pentaerythritol (di pentaerythritol, tri pentaerythritol, tetra pentaerythritol), ether, pentaerythritol formaldehyde and the like are hydrolyzed and converted into pentaerythritol, thereby recovering more pentaerythritol and improving the overall yield of pentaerythritol.

[0037] 2. The present application uses high-boiling-point methyl sulfonic acid instead of volatile and strongly corrosive formic acid and sulfuric acid, which has a high risk of affecting the hydrolysis effect and has good safety and low loss;

[0038] 3. The present application uses crude pentaerythritol for direct hydrolysis, and then hydrolysis, decolorization, secondary crystallization and purification of pentaerythritol after crystallization, thereby omitting the step of purifying the crude pentaerythritol and reducing the cost;

[0039] 4. The present invention stores the crystallization mother liquor from a specific step in the production process and uses it in the hydrolysis reaction of the raw material in the next production process, thereby reducing the amount of methanesulfonic acid used and thus lowering production costs. Furthermore, the mother liquor also contains pentaerythritol, which is stored and used in the next production process. Since the pentaerythritol circulates within the production process without flowing out of the production process, the loss of pentaerythritol is greatly reduced under repeated recycling, thereby greatly improving the overall yield of pentaerythritol.

[0040] 5. This invention uses wood-based activated carbon to decolorize byproducts such as ether and formal. Ordinary coal-based activated carbon contains large amounts of impurities such as sulfur and iron. Iron and organic matter form complexes, resulting in a yellowish color and affecting the color of the pentaerythritol product. Wood-based activated carbon, on the other hand, has well-developed pores, excellent adsorption properties, high strength, easy regeneration, and is economical and durable, reducing the color of pentaerythritol to within 30. DETAILED DESCRIPTION

[0041] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0042] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are for describing specific embodiments rather than for limiting the scope of protection of the present invention.

[0043] When numerical ranges are given in the examples, it should be understood that, unless otherwise specified herein, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs.

[0044] It is worth noting that the raw materials used in the present invention are all common commercially available products, so their sources are not specifically limited; the filtrate used in step (1) is obtained from step (2) and then recycled to step (1) for use.

[0045] Example 1

[0046] The main components of the crude pentaerythritol used in Example 1 are shown in Table 1:

[0047] Table 1 Ingredient list of crude pentaerythritol

[0048] No. Component Mass % Content 1 Monopentaerythritol 85.13 2 Dipentaerythritol 3.96 3 Tri-pentaerythritol 0.87 4 Water 9.75 5 Impurities 0.29

[0049] For the crude pentaerythritol of Table 1, the following steps are followed.

[0050] (1) The filtrate one and the crude pentaerythritol are mixed in a ratio of 3:1 by weight, then put into a dissolving kettle, and then add methanesulfonic acid to adjust the pH value of the solution to 2.2, to prepare a pentaerythritol solution one, which is hydrolyzed under heating and pressure, with a pressure of 0.23 MPa and a reaction temperature of 130°C for 4h, to obtain a hydrolyzed material one;

[0051] (2) 2.0% of 150 mesh coconut powder activated carbon of the total amount of wet material is added to the hydrolyzed material one, which is decolorized at 90°C under normal pressure for 15 min, and then filtered to remove the carbon residue and colored impurities. The mother liquor is then cooled to 30°C, stirred at a speed of 5 r / min, and crystallized for 4h, and then filtered to obtain crystal one and filtrate one, wherein the filtrate one is returned to the first step for use in the next preparation. The crystal one is dried to obtain 98% pentaerythritol, and the composition is shown in Table 2.

[0052] (3) The filtrate two and the obtained first crystal and the crude pentaerythritol are mixed in a ratio of 6:1:1, then put into a dissolving kettle, and then add methanesulfonic acid to adjust the pH value of the solution to 2.5, to prepare a pentaerythritol solution two, which is hydrolyzed under heating and pressure, with a pressure of 0.23 MPa and a reaction temperature of 130°C for 4h, to obtain a hydrolyzed material two;

[0053] (4) 2.0% of 150 mesh coconut powder activated carbon of the total amount of wet material is added to the hydrolyzed material two, which is decolorized at 90°C under normal pressure for 15 min, and then filtered to remove the carbon residue and colored impurities. The mother liquor is then cooled to 30°C, stirred at a speed of 10 r / min, and crystallized for 4h, and then filtered to obtain crystal two and filtrate two, wherein the filtrate two is returned to step (1) for use in the next preparation.

[0054] (5) The obtained crystal two is dried to obtain 99% pentaerythritol, and the specific results are shown in Table 3.

[0055] The 98% pentaerythritol and the 99% pentaerythritol prepared are detected, and the detection results are shown in Tables 2 and 3, respectively.

[0056] Table 2 Quality table of 98% pentaerythritol prepared

[0057] No. Component Quality 1 Monopentaerythritol 98.01％ 2 Color 80 3 Water 0.25％ 4 Ash 0.03％ 5 Others 1.74％ 6 Average Particle Size 40 mesh

[0058] Table 3 Quality table of 99% pentaerythritol prepared

[0059] No. Component Quality 1 Monopentaerythritol 99.71％ 2 Color 20 3 Water 0.29％ 4 Ash 0.01％ 5 Average Particle Size 80 mesh

[0060] Example 2

[0061] The crude pentaerythritol used in Example 2 has the main components shown in Table 4:

[0062] Table 4: Composition of crude pentaerythritol

[0063]

[0064]

[0065] For the crude pentaerythritol of Table 4, the following steps were followed.

[0066] (1) The filtrate one and the crude pentaerythritol were mixed in a ratio of 4:1 by weight, and then placed in a dissolving kettle. Methyl sulfonic acid was added to adjust the pH value of the solution to 2.3. A pentaerythritol solution one was prepared, and hydrolysis was carried out under heating and pressure. The pressure was 0.3 MPa, the reaction temperature was 140°C, and the time was 4 h. A hydrolyzed material one was obtained.

[0067] (2) 1.5% of 200 mesh wood powder activated carbon based on the total amount of wet material was added to the hydrolyzed material one. Decolorization was carried out at 95°C under normal pressure for 15 min. Pressure filtration was carried out to remove carbon residue and colored impurities. The mother liquor was then cooled to 35°C, and stirring was carried out at a rate of 15 r / min for 5 h. Pressure filtration was carried out to obtain crystal one and filtrate one. The filtrate one was returned to the first step for use in the next preparation. Crystal one was dried to obtain 98% pentaerythritol. The composition is shown in Table 5.

[0068] (3) The filtrate two and the obtained crystal one and the crude pentaerythritol were mixed in a ratio of 6:1:1, and then placed in a dissolving kettle. Methyl sulfonic acid was added to adjust the pH value of the solution to 2.8. A pentaerythritol solution two was prepared, and hydrolysis was carried out under heating and pressure. The pressure was 0.3 MPa, the reaction temperature was 140°C, and the time was 4 h. A hydrolyzed material two was obtained.

[0069] (4) 3.5% of 200 mesh wood powder activated carbon based on the total amount of wet material was added to the hydrolyzed material two. Decolorization was carried out at 95°C under normal pressure for 15 min. Pressure filtration was carried out to remove carbon residue and colored impurities. The mother liquor was then cooled to 35°C, and stirring was carried out at a rate of 25 r / min for 5 h. Pressure filtration was carried out to obtain filtrate two and crystal two. The filtrate two was returned to step (1) for use in the next preparation.

[0070] (5) The obtained crystal two was dried to obtain 99% pentaerythritol. The specific results are shown in Table 6.

[0071] The 98% pentaerythritol and the 99% pentaerythritol obtained were detected. The detection results are shown in Tables 5 and 6, respectively.

[0072] Table 5: Quality table of 98% pentaerythritol obtained

[0073] No. Component Quality 1 Monopentaerythritol 98.34％ 2 Color 70 3 Water 0.20％ 4 Ash 0.02％ 5 Average Particle Size 1.46％ 6 85 mesh No.

[0074] Table 6 Quality table of 99% pentaerythritol product

[0075] Component Quality Monopentaerythritol 1 Color 99.83％ 2 Water 20 3 Ash 0.17％ 4 Average Particle Size 0.02％ 5 150 mesh No.

[0076] Example 3

[0077] The pentaerythritol crude product used in Example 3 had the following main components, as shown in Table 7:

[0078] Table 7 Component table of pentaerythritol crude product

[0079] Component Mass % Content Monopentaerythritol 1 Dipentaerythritol 89.32 2 Tri-pentaerythritol 2.56 3 Water 0.61 4 Impurities 7.33 5 No. 0.18

[0080] For the pentaerythritol crude product of Table 7, the following steps were performed.

[0081] (1) The filtrate one and the pentaerythritol crude product were mixed in a ratio of 5:1 by weight, then placed in a dissolving kettle, and then methanesulfonic acid was added to adjust the pH value of the solution to 2.4, and then the temperature was raised to prepare a pentaerythritol solution one, which was subjected to pressurized hydrolysis at a pressure of 0.25 MPa and a reaction temperature of 135°C for 6 h;

[0082] (2) 1.5% of 100-mesh coconut powder activated carbon based on the total amount of wet material was added to the hydrolyzed material one, and then decolorization was performed at normal pressure and 100°C for 15 min, and then pressure filtration was performed to remove the carbon residue and colored impurities, and then the mother liquor was cooled to 40°C, and then stirring was performed at a stirring rate of 13 r / min for 6 h to crystallize, and then pressure filtration was performed to obtain crystal one and filtrate one, wherein the filtrate one was returned to the first step for use in the next preparation; and the crystal one was dried to obtain 98% pentaerythritol, and the components are shown in Table 8;

[0083] (3) Pentaerythritol solution two was prepared: the filtrate two and the obtained first crystal and pentaerythritol crude product were mixed in a ratio of 6:1:1, then placed in a dissolving kettle, then methanesulfonic acid was added to adjust the pH value of the solution to 2.9, and then the temperature was raised to prepare a pentaerythritol solution two, which was subjected to pressurized hydrolysis at a pressure of 0.15 MPa and a reaction temperature of 115°C for 6 h to obtain hydrolyzed material two;

[0084] (4) 3.5% of 100-mesh coconut powder activated carbon based on the total amount of wet material was added to the hydrolyzed material two, and then decolorization was performed at normal pressure and 100°C for 15 min, and then pressure filtration was performed to remove the carbon residue and colored impurities, and then the mother liquor was cooled to 40°C, and then stirring was performed at a stirring rate of 15 r / min for 6 h to crystallize, and then pressure filtration was performed to obtain filtrate two and crystal two, wherein the filtrate two was returned to step (1) for use in the next preparation;

[0085] (5) The obtained crystal two was dried to obtain 99% pentaerythritol product, and the specific results are shown in Table 9.

[0086] The 98% pentaerythritol and the 99% pentaerythritol products were detected, and the detection results are shown in Tables 8 and 9, respectively.

[0087] Table 8 Quality table of 98% pentaerythritol produced

[0088] Component Quality Monopentaerythritol 1 Color 98.71％ 2 Water 60 3 Ash 0.12％ 4 Others 0.01％ 5 Average Particle Size 1.17％ 6 88 mesh No.

[0089] Table 9 Quality table of 99% pentaerythritol produced

[0090] Component Quality Monopentaerythritol 1 Color 99.87％ 2 Water 20 3 Ash 0.13％ 4 Average Particle Size 0.01％ 7 93 mesh No.

[0091] Example 4

[0092] The pentaerythritol crude used in Example 4 is shown in Table 10.

[0093] Table 10 Composition table of pentaerythritol crude

[0094] Component Mass % Content Monopentaerythritol 1 Dipentaerythritol 88.07 2 Tri-pentaerythritol 3.89 3 Water 0.76 4 Impurities 7.14 5 No. 0.14

[0095] The pentaerythritol crude of Table 10 was operated according to the following steps.

[0096] (1) The filtrate one and the pentaerythritol crude were mixed in a ratio of 3.5:1 by weight, then the methanesulfonic acid was added to adjust the pH value to 2.5, the temperature was raised, and the pentaerythritol solution one was prepared. The pressure hydrolysis was carried out at a pressure of 0.20 MPa and a temperature of 125°C for 5h;

[0097] (2) 1.5% of 150 mesh coconut powder activated carbon was added to the hydrolysis material one, and the decolorization was carried out at atmospheric pressure and 105°C for 15 min. The carbon residue and colored impurities were removed by pressure filtration. The mother liquor was cooled to 45°C, and the crystallization was carried out at a stirring rate of 8 r / min for 5h. The crystal one and the filtrate one were obtained by pressure filtration. The filtrate one was returned to the first step for the next preparation. The crystal one was dried to obtain 98% pentaerythritol, and the composition is shown in Table 11;

[0098] (3) The filtrate two and the obtained first crystal and pentaerythritol crude were mixed in a ratio of 6:1:1, then the methanesulfonic acid was added to adjust the pH value to 2.8, the temperature was raised, and the pentaerythritol solution two was prepared. The pressure hydrolysis was carried out at a pressure of 0.20 MPa and a temperature of 125°C for 5h to obtain the hydrolysis material two;

[0099] (4) 2.5% of 150 mesh coconut powder activated carbon was added to the hydrolysis material two, and the decolorization was carried out at atmospheric pressure and 105°C for 15 min. The carbon residue and colored impurities were removed by pressure filtration. The mother liquor was cooled to 45°C, and the crystallization was carried out at a stirring rate of 17 r / min for 5h. The crystal two and the filtrate two were obtained by pressure filtration. The filtrate two was returned to step (1) for the next preparation;

[0100] (5) The obtained crystal is dried to obtain 99% pentaerythritol. The detailed results are shown in Table 12.

[0101] The obtained 98% pentaerythritol and 99% pentaerythritol are detected, and the detection results are shown in Tables 11 and 12, respectively.

[0102] Table 11 Quality table of prepared 98% pentaerythritol

[0103] Component Quality Monopentaerythritol 1 Color 98.52％ 2 Water 70 3 Ash 0.15％ 4 Others 0.02％ 5 Average Particle Size 1.33％ 6 70 mesh No.

[0104] Table 12 Quality table of prepared 99% pentaerythritol

[0105]

[0106]

[0107] Example 5

[0108] The crude pentaerythritol used in Example 5 has the main components shown in Table 13:

[0109] Table 13 Component table of crude pentaerythritol

[0110] Component Mass % Content Monopentaerythritol 1 Dipentaerythritol 85.16 2 Tri-pentaerythritol 4.01 3 Water 0.59 4 Impurities 10.08 5 No. 0.16

[0111] For the crude pentaerythritol in Table 13, the following steps are performed.

[0112] (1) The filtrate one and the crude pentaerythritol are mixed in a weight ratio of 4.5:1, then put into a dissolving kettle, then add methanesulfonic acid to adjust the pH value to 2.4, heat, and prepare pentaerythritol solution one, pressurized hydrolysis, pressure is 0.10 Mpa, reaction temperature is 110°C, time is 3h;

[0113] (2) 1.0% of 200 mesh wood powder activated carbon of the total amount of wet material is added to the hydrolysis material one, and the decolorization is carried out at atmospheric pressure and 110°C for 15 min, and then pressure filtration is performed to remove carbon residue and colored impurities, and the mother liquor is cooled to 50°C, the stirring rate is 20 r / min, and the crystallization is carried out for 3h, and then pressure filtration is performed to obtain crystal one and filtrate one, wherein the filtrate one is returned to the first step for next preparation; the crystal one is dried to obtain 98% pentaerythritol, and the components are shown in Table 14;

[0114] (3) The filtrate two, the obtained first crystal and the crude pentaerythritol are mixed in a ratio of 6:1:1, then put into a dissolving kettle, then add methanesulfonic acid to adjust the pH value to 3.0, heat, and prepare pentaerythritol solution two, pressurized hydrolysis, pressure is 0.10 Mpa, reaction temperature is 110°C, time is 3h, to obtain hydrolysis material two;

[0115] (4) To the hydrolyzed material two, add 2.0% of 200 mesh wood powder activated carbon of the total amount of wet material, decolorize at 110°C for 15 min under normal pressure, filter under pressure, remove carbon residue and colored impurities, and then cool the mother liquor to 50°C, stir at a speed of 35 r / min, and crystallize for 3 h at a stirring speed of 20 r / min. After pressure filtration, obtain filtrate two and crystals two, wherein the filtrate two is returned to step (1) for use in the next preparation;

[0116] (5) Dry the obtained crystals two to obtain 99% pentaerythritol. The specific results are shown in Table 15.

[0117] The 98% pentaerythritol and 99% pentaerythritol obtained are detected, and the detection results are shown in Tables 14 and 15, respectively.

[0118] Table 14 Quality table of 98% pentaerythritol obtained

[0119] Component Quality Monopentaerythritol 1 Color 98.59％ 2 Water 80 3 Ash 0.22％ 4 Others 0.02％ 5 Average Particle Size 1.19％ 6 190 mesh No.

[0120] Table 15 Quality table of 99% pentaerythritol obtained

[0121] Component Quality Monopentaerythritol 1 Color 99.25％ 2 Water 30 3 Ash 0.75％ 4 Average Particle Size 0.04％ 5 200 mesh No.

[0122] Example 6

[0123] The pentaerythritol crude used in Example 6 has the main components shown in Table 16:

[0124] Table 16 Component table of pentaerythritol crude

[0125]

[0126]

[0127] For the pentaerythritol crude of Table 16, the following steps are performed.

[0128] (1) Mix the filtrate one and the pentaerythritol crude according to a weight ratio of 3:1, and then put them into a dissolving kettle. Then add methanesulfonic acid to adjust the pH value of the solution to 2.4, heat, and prepare a pentaerythritol solution one. Hydrolyze under pressure, with a pressure of 0.15 MPa, a reaction temperature of 120°C, and a time of 4 h;

[0129] (2) To the hydrolyzed material one, add 1.5% of 150 mesh wood powder activated carbon of the total amount of wet material, decolorize at 110°C for 15 min under normal pressure, filter under pressure, remove carbon residue and colored impurities, and then cool the mother liquor to 45°C, stir at a speed of 9 r / min, and crystallize for 5 h. After pressure filtration, obtain crystals one and filtrate one, wherein the filtrate one is returned to the first step for use in the next preparation; dry the crystals one to obtain 98% pentaerythritol, and the components are shown in Table 17;

[0130] (3) The filtrate II and the primary crystals and the crude pentaerythritol obtained are mixed in a ratio of 6:1:1 and then put into a dissolving kettle, and methanesulfonic acid is added to adjust the pH value of the solution to 2.8, and a pentaerythritol solution II is prepared by heating and pressurized hydrolysis, the pressure is 0.15 MPa, the reaction temperature is 120°C, and the time is 4h, to obtain a hydrolyzed material II;

[0131] (4) 3.5% of 150 mesh wood powder activated carbon of the total amount of wet material is added to the hydrolyzed material II, and decolorization is carried out at normal pressure and 110°C for 15 min, and then pressure filtration is performed to remove carbon residue and colored impurities, and the mother liquor is cooled to 45°C again, and the stirring rate is 11 r / min, and crystallization is carried out for 5h, and the stirring rate during crystallization is 22 r / min, and then pressure filtration is performed to obtain the filtrate II and the crystals II, wherein the filtrate II is returned to step (1) for use in the next preparation;

[0132] (5) The crystals II obtained are dried to obtain 99% pentaerythritol, and the specific results are shown in Table 18.

[0133] The 98% pentaerythritol and the 99% pentaerythritol obtained are detected, and the detection results are shown in Tables 17 and 18, respectively.

[0134] Table 17 Quality table of 98% pentaerythritol obtained

[0135] Component Quality Monopentaerythritol 1 Color 98.62％ 2 Water 90 3 Ash 0.25％ 4 Others 0.03％ 5 Average Particle Size 1.13％ 6 75 mesh No.

[0136] Table 18 Quality table of 99% pentaerythritol obtained

[0137] Component Quality Monopentaerythritol 1 Color 99.45％ 2 Water 20 3 Ash 0.55％ 4 Average Particle Size 0.03％ 5 87 mesh No.

[0138] Comparative Example 1

[0139] Comparative Example 1 uses the crude pentaerythritol of Example 1 (the specific components are shown in Table 1), and the catalyst uses phosphoric acid, and the specific operation steps are as follows:

[0140] (1) The filtrate I and the crude pentaerythritol are mixed in a ratio of 3:1 by weight, and then put into a dissolving kettle, and phosphoric acid is added to adjust the pH value of the solution to 2.2, and a pentaerythritol solution I is prepared by heating and pressurized hydrolysis, the pressure is 0.23 MPa, the reaction temperature is 130°C, and the time is 4h, to obtain a hydrolyzed material I;

[0141] (2) 2.0% of 150 mesh coconut shell powder activated carbon of the total amount of wet material is added to the hydrolyzed material I, and decolorization is carried out at normal pressure and 90°C for 15 min, and then pressure filtration is performed to remove carbon residue and colored impurities, and the mother liquor is cooled to 30°C again, and the stirring rate is 5 r / min, and crystallization is carried out for 4h, and then pressure filtration is performed to obtain the crystals I and the filtrate I, wherein the filtrate I is returned to the first step for use in the next preparation; and the crystals I are dried to obtain 98% pentaerythritol, and the components are shown in Table 19;

[0142] (3) The filtrate two and the primary crystal and crude pentaerythritol obtained are mixed in a ratio of 6:1:1, and then put into a dissolving kettle. Phosphoric acid is added to adjust the pH value of the solution to 2.5, and a pentaerythritol solution two is prepared. The solution is hydrolyzed under heating and pressurization. The pressure is 0.23 MPa, the reaction temperature is 130°C, and the reaction time is 4 h. A hydrolyzed material two is obtained;

[0143] (4) 2.0% of 150-mesh coconut powder activated carbon based on the total amount of the wet material is added to the hydrolyzed material two. The solution is decolorized at 90°C under normal pressure for 15 min, and then filtered to remove the carbon residue and colored impurities. The mother liquor is cooled to 30°C, and then crystallized for 4 h under stirring at a speed of 10 r / min. The stirring speed is 20 r / min. The filtrate two and the crystal two are obtained after filtration. The filtrate two is returned to step (1) for use in the next preparation;

[0144] (5) The crystal two is dried to obtain 99% pentaerythritol. The specific results are shown in Table 20.

[0145] The 98% pentaerythritol and the 99% pentaerythritol obtained are detected. The detection results are shown in Tables 19 and 20, respectively.

[0146] Table 19 Quality table of 98% pentaerythritol obtained

[0147] Component Quality Monopentaerythritol 1 Color 96.87％ 2 Water 100 3 Ash 0.44％ 4 Others 0.14％ 5 Average Particle Size 2.69％ 6 40 mesh No.

[0148] Table 20 Quality table of 99% pentaerythritol obtained

[0149]

[0150]

[0151] Comparative Example 2

[0152] Comparative Example 2 uses the crude pentaerythritol of Example 2 (the specific components are shown in Table 4), and the catalyst is phosphoric acid. The specific operation steps are as follows:

[0153] (1) The filtrate one and the crude pentaerythritol are mixed in a ratio of 4:1 by weight, and then put into a dissolving kettle. Methanesulfonic acid is added to adjust the pH value of the solution to 2.3, and a pentaerythritol solution one is prepared. The solution is hydrolyzed under heating and pressurization. The pressure is 0.1 MPa, the reaction temperature is 90°C, and the reaction time is 4 h. A hydrolyzed material one is obtained;

[0154] (2) to the hydrolysis material one, add 1.5% of the total amount of wet material of 200 mesh wood powder activated carbon, decolorization at 95°C for 15 min under normal pressure, filter pressing, remove carbon residue and colored impurities, the mother liquor is cooled to 35°C, stirring rate is 15 r / min, crystallization for 5 h, filter pressing, to obtain crystal one and filtrate one, wherein the filtrate one returns to the first step for next preparation; dry the crystal one, 98% pentaerythritol can be obtained, see table 21 for composition;

[0155] (3) mix the filtrate two with the obtained first crystal and pentaerythritol crude product according to the ratio of 6:1:1, then put into the dissolving kettle, then add methanesulfonic acid to adjust the pH value of the solution to 2.8, heat, configure to obtain pentaerythritol solution two, hydrolysis under pressure, pressure is 0.1 Mpa, reaction temperature is 90°C, time is 4 h, to obtain hydrolysis material two;

[0156] (4) to the hydrolysis material two, add 3.5% of the total amount of wet material of 200 mesh wood powder activated carbon, decolorization at 95°C for 15 min under normal pressure, filter pressing, remove carbon residue and colored impurities, the mother liquor is cooled to 35°C, stirring rate is 25 r / min, crystallization for 5 h, the stirring rate of crystallization is 22 r / min, filter pressing to obtain filtrate two and crystal two, wherein the filtrate two returns to step (1) for next preparation;

[0157] (5) dry the obtained crystal two, 99% pentaerythritol finished product is obtained, see table 22 for specific results.

[0158] The prepared 98% pentaerythritol and 99% pentaerythritol are detected, and the detection results are shown in tables 21 and 22 respectively.

[0159] Table 21 quality table of prepared 98% pentaerythritol

[0160] Component Quality Monopentaerythritol 1 Color 96.86％ 2 Water 100 3 Ash 0.37％ 4 Others 0.15％ 5 Average Particle Size 2.77％ 6 85 mesh No.

[0161] Table 22 quality table of prepared 99% pentaerythritol

[0162] Component Quality Monopentaerythritol 1 Color 97.43％ 2 Water 60 3 Ash 0.29％ 4 Others 0.08％ 5 Average Particle Size 2.28％ 6 150 mesh No.

[0163] Comparative example 3

[0164] Comparative example 3 uses the pentaerythritol crude product of example 3 (see table 7 for specific composition), and the catalyst uses phosphoric acid, and the specific operation steps are as follows:

[0165] (1) mix the filtrate one with the pentaerythritol crude product according to the weight ratio of 5:1, then put into the dissolving kettle, then add methanesulfonic acid to adjust the pH value of the solution to 3.5, heat, configure to obtain pentaerythritol solution one, hydrolysis under pressure, pressure is 0.25 Mpa, reaction temperature is 135°C, time is 6 h;

[0166] (2) to the hydrolysis material one, add 1.5% of 100 mesh coconut shell powder activated carbon of total wet material, decolorization at 100℃ for 15min under normal pressure, pressure filtration, remove carbon residue and colored impurities, the mother liquor is cooled to 40℃, stirring rate 13r / min, crystallization 6h, pressure filtration, get crystal one and filtrate one, wherein, the filtrate one returns to the first step for next preparation; the crystal one is dried, 98% pentaerythritol can be obtained, see table 23 for composition;

[0167] (3) preparation of pentaerythritol solution two: the filtrate two and the obtained first crystal and pentaerythritol crude product are mixed according to the ratio of 6:1:1, then put into the solution kettle, then add methanesulfonic acid to adjust the pH value of the solution to 4.0, heat, and prepare pentaerythritol solution two, pressure hydrolysis, pressure 0.15Mpa, reaction temperature 115℃, time 6h, get hydrolysis material two;

[0168] (4) to the hydrolysis material two, add 3.5% of 100 mesh coconut shell powder activated carbon of total wet material, decolorization at 100℃ for 15min under normal pressure, pressure filtration, remove carbon residue and colored impurities, the mother liquor is cooled to 40℃, stirring rate 15r / min, crystallization 6h, crystallization stirring rate 18r / min, pressure filtration, get filtrate two and crystal two, wherein, the filtrate two returns to step (1) for next preparation;

[0169] (5) the obtained crystal two is dried, 99% pentaerythritol finished product is obtained, see table 24 for specific results.

[0170] The prepared 98% pentaerythritol and 99% pentaerythritol are detected, and the detection results are shown in table 23 and 24 respectively.

[0171] Table 23 quality table of prepared 98% pentaerythritol

[0172] Component Quality Monopentaerythritol 1 Color 96.51％ 2 Water 100 3 Ash 0.41％ 4 Others 0.18％ 5 Average Particle Size 3.08％ 6 88 mesh ​

[0173] Table 24 quality table of prepared 99% pentaerythritol

[0174]

[0175]

[0176] From the results, it can be seen that the commonly used acid phosphoric acid in industrial pentaerythritol hydrolysis is replaced by the methanesulfonic acid used in the present application, and under the same conditions, neither the purity nor the color value can reach the level of the present application.

[0177] Finally, it should be pointed out that the above content is only used to illustrate the technical scheme of the present application, and is not a limitation on the protection scope of the present application. Simple modification or equivalent replacement of the technical scheme of the present application by ordinary skilled in the art does not deviate from the essence and scope of the technical scheme of the present application.

Claims

1. A process for the production of 98% pentaerythritol co-produced with 99% pentaerythritol, characterized by: The method comprises the following steps: (1) mixing water and crude pentaerythritol, adding methanesulfonic acid to adjust pH, obtaining pentaerythritol solution I, and then hydrolyzing under heating and pressurization to obtain hydrolyzate I; the crude pentaerythritol comprises 85-90% of mono-pentaerythritol, 3-5% of di-pentaerythritol, 0.5-1% of tri-pentaerythritol, and the balance of water; the pH of the pentaerythritol solution I is 2-2.5; (2) decolorizing, filter-pressing, crystallizing, and filter-pressing again the hydrolyzate I obtained in step (1) to obtain crystals I and filtrate I, and drying the crystals I to obtain 98% pentaerythritol; (3) mixing the crystals I obtained in step (2) and crude pentaerythritol, adding methanesulfonic acid to adjust pH, obtaining pentaerythritol solution II, and then hydrolyzing under heating and pressurization to obtain hydrolyzate II; the pH of the pentaerythritol solution II is 2.5-3; (4) decolorizing, filter-pressing, crystallizing, and filter-pressing again the hydrolyzate II obtained in step (3) to obtain crystals II and filtrate II; (5) drying the crystals II obtained in step (4) to obtain 99% pentaerythritol.

2. The method of claim 1, wherein: The weight ratio of the water to the crude pentaerythritol in step (1) is 3-5:

1.

3. The method of claim 2, wherein: The weight ratio of the water to the crude pentaerythritol in step (1) is 3:

1.

4. The method of claim 1, wherein: The temperature of the heating in steps (1) and (3) is 110-140°C, the time is 3-6h, and the pressure of the pressurized hydrolysis is 0.1-0.3Mpa; the decolorizing conditions in steps (2) and (4) are: temperature 90-110°C, time 15min, and normal pressure; the crystallizing temperature in steps (2) and (4) is 30-50°C, and the time is 3-6h.

5. The method of claim 1, wherein: The decolorizing in steps (2) and (4) is specifically carried out by adding activated carbon, and the particle size is 100-200mesh; the addition amount of the activated carbon in step (2) is 1.0-2.0% of the total weight of the crude pentaerythritol, and the addition amount of the activated carbon in step (4) is 2.0-4.0% of the total weight of the crude pentaerythritol.

6. The method of claim 5, wherein: The activated carbon comprises coconut shell powder activated carbon and / or wood powder activated carbon.

7. The method of claim 1, wherein: When the stirring rate of the crystallizing in step (4) is 5-10r / min, the crystal size is 40-80mesh; when the stirring rate is 10-20r / min, the crystal size is 80-100mesh; and when the stirring rate is 20r / min or more, the crystal size is 100-200mesh.

8. The method of claim 1, wherein: The filtrate I in step (2) and the filtrate II in step (4) are both returned to the preparation process of the pentaerythritol solution I in step (1) and / or the preparation process of the pentaerythritol solution II in step (3) to replace water.

9. The method of claim 8, wherein: The weight ratio of the filtrate II, the crystals I, and the crude pentaerythritol in step (3) is 5-7:1:

1.

10. The method of claim 9, wherein: The weight ratio of the filtrate II, the crystals I, and the crude pentaerythritol in step (3) is 6:1:1.

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