Post-treatment method of neopentyl glycol reaction liquid

Abstract

The invention provides a post-treatment method of neopentyl glycol reaction liquid, which comprises the following steps: (1) sequentially removing water and light components from the neopentyl glycol reaction liquid to obtain crude neopentyl glycol; and (2) carrying out hydrogenation reaction on the crude neopentyl glycol to obtain a neopentyl glycol product. According to the invention, membrane separation and hydrogenation are adopted to replace original rectification thermal separation, so that the energy consumption of the device can be obviously reduced. And heavy components can be converted into neopentyl glycol by means of hydrogenation, so that the material consumption of the device can be reduced. Meanwhile, the acid value of the product can be effectively reduced, high economic benefits are created, and the competitiveness of the device is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of neopentyl glycol preparation and relates to a post-treatment method of a neopentyl glycol reaction liquid. Background Art

[0002] Neopentyl glycol is an important chemical intermediate. It is mainly used in the production of oil-free alkyd resins, polyester powder coatings, unsaturated polyester resins, printing inks, synthetic plasticizers and aviation lubricants. This product has good thermal stability, acid resistance, alkali resistance and weather resistance. It is widely used in coatings, construction and insulation materials industries. 80% of the world's neopentyl glycol is used in the coatings industry.

[0003] Neopentyl glycol is usually prepared in industry by two methods: disproportionation and condensation hydrogenation. The disproportionation method is to use a strong alkaline catalyst, such as sodium hydroxide, potassium hydroxide or calcium hydroxide, to make isobutyraldehyde and formaldehyde aqueous solution generate neopentyl glycol and formate under the action of an alkaline catalyst, and then the reaction mixture is desalted and refined to obtain a qualified product. The disadvantage of this method is that a large amount of formate is formed as a by-product.

[0004] The condensation hydrogenation method is to react formaldehyde aqueous solution and isobutyraldehyde under the action of organic amine catalyst, and the reaction product is hydrogenated to generate a mixture of neopentyl glycol, which contains a large amount of water and acidic substances. The neopentyl glycol mixture is distilled to remove water and other light components, and the tower bottom after light removal is distilled to remove heavy components, and finally obtain industrial pure neopentyl glycol.

[0005] Patent CN115894169B relates to a production process of high-purity neopentyl glycol. It uses formaldehyde aqueous solution and isobutylaldehyde as raw materials, reacts under the catalytic action of trimethylamine, and purifies the liquid by distillation. The resulting hydroxyl neopentylaldehyde aqueous solution is then hydrogenated under the condition of a copper-containing catalyst. After hydrogenation, the liquid is degassed and distilled under reduced pressure to obtain neopentyl glycol with a purity of more than 99.0wt%. Its production process involves multiple distillation processes, which consumes a lot of energy and is prone to material loss during the distillation process.

[0006] Patent CN109796334A provides an intermittent process for recovering tyrol esters from neopentyl glycol waste liquid. Before distilling the waste liquid, the trivalent iron ions in the waste liquid are removed by adding alkali solution under mild conditions. During the distillation process, the distillation is carried out at a lower temperature (not exceeding 160°C) to prevent the tyrol esters from being decomposed by heat, thereby increasing the yield of tyrol esters by more than 30%. The invention improves the operating competitiveness of the device by recovering esters from the heavy components, but its intermittent production method, complex production process, and large losses and energy consumption during the distillation process make it less operable. Summary of the invention

[0007] In view of this, the purpose of the present invention is to solve the problems of energy consumption, material consumption, high acid value and the like in the existing production process of preparing neopentyl glycol by hydrogenation. Therefore, a post-treatment method of a neopentyl glycol reaction liquid is proposed. After removing water and light components from a neopentyl glycol-containing solution obtained by a hydrogenation reaction, a hydrogenation reaction is performed again to hydrogenate the heavy components therein into neopentyl glycol. The method can significantly reduce the energy consumption of the device and the acid value of the product, and can separate a high-purity neopentyl glycol product from the neopentyl glycol hydrogenation reaction liquid at a low cost.

[0008] The technical solution for achieving the purpose of the present invention is as follows:

[0009] A post-treatment method for a neopentyl glycol reaction solution comprises the following steps:

[0010] (1) removing water and light components from the neopentyl glycol reaction solution to obtain crude neopentyl glycol;

[0011] (2) The crude neopentyl glycol is subjected to hydrogenation reaction to obtain a neopentyl glycol product.

[0012] In a specific embodiment of the present invention, the neopentyl glycol reaction liquid in step (1) is a neopentyl glycol hydrogenation reaction liquid, that is, a hydrogenation product after passing through a hydrogenation reactor in a process for preparing neopentyl glycol by hydrogenation; preferably, a mixture containing neopentyl glycol obtained by condensation and hydrogenation in a process for producing neopentyl glycol by hydrogenation.

[0013] For example, optionally, in some examples, the mass percentage composition of the neopentyl glycol reaction liquid includes 30-70wt% neopentyl glycol, 10-50wt% water, 1-10wt% methanol, 1-10wt% isobutanol, 0.01-3wt% trimethylamine, 10-10000ppm formic acid, 10-10000ppm isobutyric acid, 10-10000ppm hydroxypivalic acid, 10-10000ppm hydroxypivalic acid neopentyl glycol ester and other trace impurities.

[0014] In a specific embodiment of the present invention, the water in step (1) is removed by membrane separation;

[0015] Preferably, the type of the membrane in the membrane separation method is one or a combination of two or more of an organic molecular sieve membrane and an inorganic molecular sieve membrane, preferably an inorganic molecular sieve membrane.

[0016] In a specific embodiment of the present invention, in step (1), the neopentyl glycol reaction solution is dehydrated to a water content of 0 to 50 wt %, preferably 10 to 35 wt %.

[0017] In a specific embodiment of the present invention, the light components in step (1) are removed by distillation;

[0018] Preferably, the distillation operation has a pressure of 0.006-0.05 MPa, preferably 0.01-0.04 MPa, and a temperature of 50-200°C, preferably 120-190°C.

[0019] In a specific embodiment of the present invention, in step (1), the crude neopentyl glycol is obtained by removing light components from the neopentyl glycol reaction solution, wherein the light components refer to components having a boiling point lower than that of neopentyl glycol, including one or more of methanol, isobutanol, trimethylamine, formic acid, isobutyric acid, etc.;

[0020] The crude neopentyl glycol comprises, by weight percentage, 90-98 wt % of neopentyl glycol, 0.1-3 wt % of hydroxypivalic acid neopentyl glycol ester and 0.1-3 wt % of hydroxypivalic acid, and other trace impurities.

[0021] In a specific embodiment of the present invention, the hydrogenation reaction in step (2) further comprises adding a hydrogenation catalyst to the reaction system, wherein the hydrogenation catalyst is selected from one or more copper-based hydrogenation catalysts;

[0022] Preferably, the copper-based hydrogenation catalyst contains three metal elements of copper, zinc and aluminum, or contains four metal elements of copper, zinc, aluminum and manganese, and more preferably contains four metal elements of copper, zinc, aluminum and manganese.

[0023] The copper-based hydrogenation catalyst containing four metal elements of copper, zinc, aluminum and manganese comprises 20-50wt% of copper oxide, 20-40wt% of zinc oxide, 20-40wt% of aluminum oxide and 1-10wt% of manganese oxide by weight percentage, preferably 30-40wt% of copper oxide, 25-35wt% of zinc oxide, 25-35wt% of aluminum oxide and 5-10wt% of manganese oxide.

[0024] In a specific embodiment of the present invention, the conditions of the hydrogenation reaction in step (2) are: reaction temperature of 80-120° C., hydrogen pressure of 3.0-4.5 MPa, and reaction time of 10-60 min.

[0025] In the present invention, step (2) can convert the heavy components in the neopentyl glycol reaction solution into neopentyl glycol through the hydrogenation system, and the converted heavy components include hydroxypivalic acid neopentyl glycol ester, hydroxypivalic acid and other trace impurities.

[0026] In the present invention, the purity of the separated neopentyl glycol product can reach above 99.50wt%.

[0027] The energy consumption per ton of neopentyl glycol production can be reduced to less than 100 kg of standard coal, the butyraldehyde consumption per ton of neopentyl glycol product can be reduced to less than 710 kg, and the acid value can be reduced to less than 40 ppm.

[0028] Compared with the traditional separation production of NPG, the separation method of the present invention can reduce the energy consumption of hydrogenation production of neopentyl glycol by more than 80%, the butyraldehyde consumption per ton of neopentyl glycol product can be reduced by more than 5kg, and the acid value can be reduced by more than 20ppm.

[0029] Compared with the prior art, the present invention has at least the following advantages and positive effects:

[0030] The method for separating pure neopentyl glycol from neopentyl glycol reaction liquid of the present invention has the advantages of reducing energy consumption, butyraldehyde consumption, acid value, etc. of producing neopentyl glycol by hydrogenation, and the quality content of neopentyl glycol product can reach more than 99.5wt%. It is beneficial to the development of producing neopentyl glycol by hydrogenation, can create higher economic benefits, and further improve the market competitiveness of industries and enterprises. DETAILED DESCRIPTION

[0031] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0032] The present invention provides a post-treatment method for a neopentyl glycol reaction solution, comprising the following steps:

[0033] (1) removing water and light components from the neopentyl glycol reaction solution to obtain crude neopentyl glycol;

[0034] (2) The crude neopentyl glycol is subjected to hydrogenation reaction to obtain a neopentyl glycol product.

[0035] In the above-mentioned post-treatment method, the water and light components of the neopentyl glycol reaction liquid obtained by the reaction are removed, and then the heavy components are hydrogenated to convert into neopentyl glycol, which can significantly reduce the energy consumption of the device and the acid value of the product, and directly obtain industrial pure neopentyl glycol. The purity of the neopentyl glycol product can reach more than 99.50wt%. The energy consumption per ton of neopentyl glycol production can be reduced to less than 100kg of standard coal, the butyraldehyde consumption per ton of neopentyl glycol product can be reduced to less than 710kg, and the acid value can be reduced to less than 40ppm.

[0036] In the specific embodiment provided by the present invention, the neopentyl glycol reaction liquid in the above step (1) is a neopentyl glycol hydrogenation reaction liquid, that is, a hydrogenation product after passing through a hydrogenation reactor in a process for preparing neopentyl glycol by hydrogenation; preferably, it is a mixture containing neopentyl glycol obtained by condensation and hydrogenation in a process for producing neopentyl glycol by hydrogenation; any neopentyl glycol reaction liquid obtained by an existing known hydrogenation process is applicable to the method of the present invention; for example, one of the hydrogenation methods is to use formaldehyde and isobutyraldehyde as raw materials, and react with trimethylamine or triethylamine to obtain a reaction liquid, which contains neopentyl glycol, a large amount of water and other substances, as well as light components (including methanol, isobutanol, trimethylamine or triethylamine, formic acid, isobutyric acid, etc.), and heavy components (including hydroxypivalic acid neopentyl glycol ester, hydroxypivalic acid and other trace impurities, etc.);

[0037] Specifically, the neopentyl glycol reaction solution may include, by weight percentage, 30-70 wt% of neopentyl glycol (e.g., 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, etc. or a range consisting of any two of them), 10-50 wt% of water (e.g., 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, etc. or a range consisting of any two of them), 1-10 wt% of methanol (e.g., 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt% or the like or a range consisting of any two thereof), 1-10wt% of isobutyl alcohol (e.g., 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt% or the like or a range consisting of any two thereof), 0.01-3wt% of trimethylamine (e.g., 0.01wt%, 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt% or the like or a range consisting of any two thereof), 10-15wt% of 10000 ppm of formic acid (e.g., 10 ppm, 50 ppm, 100 ppm, 500 ppm, 1000 ppm, 2000 ppm, 4000 ppm, 6000 ppm, 8000 ppm, 10000 ppm, etc., or a range consisting of any two thereof), 10 to 10000 ppm of isobutyric acid (e.g., 10 ppm, 50 ppm, 100 ppm, 500 ppm, 1000 ppm, 2000 ppm, 4000 ppm, 6000 ppm, 8000 ppm, 10000 ppm, etc., or a range consisting of any two thereof), 10 to 10000 ppm 10 ppm, 50 ppm, 100 ppm, 500 ppm, 1000 ppm, 2000 ppm, 4000 ppm, 6000 ppm, 8000 ppm, 10000 ppm, etc., or a range consisting of any two of them; 10 to 10000 ppm of hydroxypivalic acid neopentyl glycol ester (e.g., 10 ppm, 50 ppm, 100 ppm, 500 ppm, 1000 ppm, 2000 ppm, 4000 ppm, 6000 ppm, 8000 ppm, 10000 ppm, etc., or a range consisting of any two of them; and other trace impurities.

[0038] In the specific embodiment provided by the present invention, the water in the above step (1) is removed by a membrane separation method; the raw material after hydrogenation enters the membrane separation device, and after being treated by the membrane separation device, wastewater containing a small amount of organic matter such as methanol and isobutanol and a dehydrated concentrated liquid are obtained respectively;

[0039] Among them, the type of membrane in the membrane separation method is one or two or more combinations of organic molecular sieve membranes and inorganic molecular sieve membranes, such as NaA-type inorganic molecular sieve membranes of Huiyong, molecular sieve membranes of Lanjing, organic-inorganic composite membranes of Pantech, etc.;

[0040] Specifically, in some embodiments, the type of the membrane may be an inorganic molecular sieve membrane, such as an inorganic molecular sieve pervaporation membrane.

[0041] In the specific embodiments provided by the present invention, the neopentyl glycol reaction liquid in the above step (1) can be subjected to membrane separation to remove part or all of the water in the hydrogenation liquid to a water content of 0 to 50 wt%, for example, 0 wt%, 0.01 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, or the like, or any two thereof.

[0042] In an embodiment of the present invention, the processing capacity of a single membrane separation device is 1 to 5 t / h, for example, 1 t / h, 2 t / h, 3 t / h, 4 t / h, 5 t / h, etc. or a range consisting of any two of them; the processing capacity can also be increased by connecting multiple membrane separation devices in parallel.

[0043] In an embodiment of the present invention, the wastewater separated and removed may include water, methanol, isobutanol, neopentyl glycol, trimethylamine, etc., for example, its mass percentage composition is 90-99wt% water, 0.1-3wt% methanol, 0.1-3wt% isobutanol, 0.1-3wt% neopentyl glycol, 10-1000ppm trimethylamine, and other trace impurities.

[0044] At the same time, the concentrated liquid obtained by separation may include neopentyl glycol, methanol, isobutanol, hydroxypivalic acid neopentyl glycol ester, hydroxypivalic acid, water, trimethylamine, etc. For example, its mass percentage composition is 45-98wt% of neopentyl glycol, 0.1-3wt% of methanol, 0.1-3wt% of isobutanol, 0.1-3wt% of hydroxypivalic acid neopentyl glycol ester, 0.1-3wt% of hydroxypivalic acid, 0-50wt% of water, 10-10000ppm of trimethylamine, and other trace impurities.

[0045] In the specific embodiment provided by the present invention, the concentrated liquid after dehydration in the above step (1) enters a light component removal operation unit to remove light components in the concentrated liquid. The dehydration and light component removal operations can be performed sequentially, wherein the light components can be removed by conventional methods in the field, such as vacuum distillation and other separation operations;

[0046] Specifically, in some embodiments, the light components are removed by distillation, the concentrated liquid enters a light-removing tower, the light components are removed from the top of the tower, and crude neopentyl glycol is obtained from the bottom of the tower; wherein the light components refer to components with a boiling point lower than that of neopentyl glycol, including one or more of methanol, isobutanol, trimethylamine, formic acid, isobutyric acid, etc.

[0047] Wherein, the distillation operation has a pressure of 0.006-0.1 MPa, such as 0.006 MPa, 0.015 MPa, 0.03 MPa, 0.05 MPa, 0.08 MPa, 0.1 MPa, etc., or a range consisting of any two thereof, and a temperature of 50-200°C, such as 50°C, 70°C, 90°C, 100°C, 120°C, 140°C, 150°C, 170°C, 190°C, 200°C, etc., or a range consisting of any two thereof;

[0048] The number of theoretical plates of the light removal tower is 5 to 30, for example, 5, 10, 15, 20, 25, 30, or any two thereof; the feed position is the 10th to 29th plate, for example, the 10th, 12th, 15th, 18th, 20th, 23rd, 25th, 27th, 29th plate, or any two thereof; the operating pressure is 0.006 to 0.1 MPa, for example, 0.006 MPa, 0.015 MPa, 0.03 MPa, 0.06 MPa, 0.08 MPa, 0.10 MPa, 0.11 MPa, 0.16 MPa, 0.17 MPa, 0.18 MPa, 0.20 MPa, 0.21 MPa, 0.23 MPa, 0.24 MPa, 0.26 MPa, 0.27 MPa, 0.28 MPa, 0.29 MPa, 0.30 MPa, 0.31 MPa, 0.32 MPa, 0.33 MPa, 0.36 MPa, 0.37 MPa, 0.38 MPa, 0.39 MPa, 0.40 MPa, 0.41 MPa, 0.42 MPa, 0.43 MPa, 0.44 MPa, 0.45 MPa, 0.46 MPa, 0.47 MPa, 0.48 MPa, 0.49 MPa, 0.50 MPa, .05MPa, 0.08MPa, 0.1MPa, etc. or any two thereof; the reflux ratio is 0.1-20, such as 0.1, 0.5, 1, 5, 10, 15, 20, etc. or any two thereof; the bottom temperature is 50-200°C, such as 50°C, 70°C, 90°C, 100°C, 120°C, 140°C, 150°C, 170°C, 190°C, 200°C, etc. or any two thereof. In some specific embodiments, the theoretical plate number of the above-mentioned light removal tower is 10-20; the feed position is the 15th to 19th plate; the operating pressure is 0.1-0.4atm; the reflux ratio is 1-5; and the bottom temperature is 120-190°C.

[0049] In the embodiment of the present invention, the neopentyl glycol content in the light components removed from the top of the light removal tower is less than 5wt%, and in some specific embodiments, less than 2wt%;

[0050] At the same time, after removing the light components, crude neopentyl glycol is obtained, which may include neopentyl glycol, hydroxypivalate neopentyl glycol ester, hydroxypivalic acid, etc., for example, the mass percentage composition is 90-98wt% of neopentyl glycol, 0.1-3wt% of hydroxypivalate neopentyl glycol ester and 0.1-3wt% of hydroxypivalic acid, and other trace impurities.

[0051] In the specific embodiment provided by the present invention, the hydrogenation reaction in the above step (2) can convert the heavy components in the neopentyl glycol reaction solution into neopentyl glycol, and the converted heavy components include hydroxypivalic acid neopentyl glycol ester, hydroxypivalic acid and other trace impurities.

[0052] The above hydrogenation reaction can be carried out using conventional reactors and conventional processes in the art, for example, batch, semi-batch, continuous or other reactors.

[0053] Specifically, in the above hydrogenation reaction, the system comprises a hydrogenation catalyst, which may be a conventional metal catalyst, a supported catalyst or other hydrogenation catalyst. In some specific embodiments of the present invention, a metal catalyst is used, which includes a metal oxide, which may be a mixture of metal oxides, or an oxygen-containing compound containing multiple metal elements at the same time;

[0054] In some specific embodiments, the hydrogenation catalyst is one or more of copper-based hydrogenation catalysts;

[0055] Specifically, the copper-based hydrogenation catalyst contains three metal elements of copper, zinc and aluminum, or contains four metal elements of copper, zinc, aluminum and manganese. More specifically, the copper-based hydrogenation catalyst contains four metal elements of copper, zinc, aluminum and manganese.

[0056] The copper-based hydrogenation catalyst containing four metal elements of copper, zinc, aluminum and manganese comprises 20-50 wt% of copper oxide (e.g., 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt% or any two thereof), 20-40 wt% of zinc oxide (e.g., 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt% or any two thereof), 20-40 wt% of aluminum oxide (e.g., 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt% or any two thereof) and 1-10 wt% (e.g., 10 wt%, 3 wt%, 5 wt%, 7 wt%, 10 wt% or any two thereof) of manganese oxide. In some specific embodiments, the copper-based hydrogenation catalyst containing four metal elements of copper, zinc, aluminum and manganese comprises 30-40 wt% of copper oxide, 25-35 wt% of zinc oxide, 25-35 wt% of aluminum oxide and 5-10 wt% of manganese oxide in weight percentage.

[0057] Specifically, in some embodiments, the amount of the hydrogenation catalyst is determined according to conventional processes, which is specifically determined by the reaction time and the feed flow rate. For example, the amount of the hydrogenation catalyst is such that the corresponding residence time is 10 to 60 minutes.

[0058] In a specific embodiment of the present invention, specifically, the conditions of the above-mentioned hydrogenation reaction can be: the reaction temperature is 80-120°C, for example, 80°C, 90°C, 100°C, 110°C, 120°C, etc. or a range consisting of any two thereof, the hydrogen pressure is 3.0-4.5MPa, for example, 3.0MPa, 3.5MPa, 4.0MPa, 4.5MPa, etc. or a range consisting of any two thereof, and the reaction time is 10-60min, for example, 10min, 20min, 30min, 40min, 50min, 60min, etc. or a range consisting of any two thereof, which is beneficial to improve the conversion rate of the heavy component and the selectivity of neopentyl glycol, and improve the yield of neopentyl glycol.

[0059] Specifically, during the above hydrogenation reaction, the amount of hydrogen added satisfies the above hydrogen pressure (ie, hydrogen is charged into the reactor and the hydrogen is pressurized to a preset hydrogen pressure). In specific implementation, hydrogen can be fed continuously or intermittently.

[0060] In the embodiment of the present invention, the crude neopentyl glycol in step (3) above enters the hydrogenation system to convert the heavy components in the crude butanol to obtain industrially pure neopentyl glycol, the purity of which can reach more than 99.50wt%;

[0061] Specifically, the obtained industrial pure neopentyl glycol may include a small amount of hydroxypivalate neopentyl glycol ester, hydroxypivalic acid, etc., for example, 0.001-0.1wt% of hydroxypivalate neopentyl glycol ester, 0.001-0.1wt% of hydroxypivalic acid, 1-50ppm of formic acid, 1-100ppm of isobutyric acid and other trace impurities.

[0062] The following examples will further illustrate the method provided by the present invention, but the present invention is not limited to the listed examples, and should also include any other known changes within the scope of the rights claimed by the present invention.

[0063] In each embodiment and comparative example of the present invention, the preparation method of the raw material neopentyl glycol reaction liquid is: using 37wt% formaldehyde aqueous solution and isobutylaldehyde as raw materials, trimethylamine or triethylamine as catalyst, reacting at a reaction temperature of 65-75°C under a pressure of 0.1-0.3MPa for 30min, and then undergoing a one-step hydrogenation reaction to obtain a neopentyl glycol reaction liquid.

[0064] Unless otherwise specified, other raw materials and reagents were purchased from commercial sources.

[0065] The main equipment information used in the embodiments and comparative examples of the present invention is as follows:

[0066] Membrane separation equipment: The type of membrane is inorganic molecular sieve pervaporation membrane;

[0067] Other equipment such as lightness removal tower, reactor, etc., unless otherwise specified, are of conventional types in the field.

[0068] The main analytical methods used in the examples and comparative examples of the present invention are as follows:

[0069] Production energy consumption: Calculate the steam consumption during the production process and convert it into standard coal;

[0070] Acid value: Tested using an acid-base neutralization titrator;

[0071] Content: Tested by gas chromatography.

[0072] Example 1

[0073] The neopentyl glycol reaction liquid comprises the following components in percentage by weight: 33.02 wt% of water, 60.45 wt% of neopentyl glycol, 2.57 wt% of methanol, 1.04 wt% of trimethylamine, 1.11 wt% of isobutyl alcohol, 0.2 wt% of hydroxypivalic acid, 0.58 wt% of hydroxypivalic acid neopentyl glycol ester, 2000 ppm of formic acid, and 500 ppm of isobutyric acid.

[0074] Post-treatment method of neopentyl glycol reaction liquid:

[0075] 1) The neopentyl glycol reaction liquid enters the membrane separation device with a feed flow rate of 5 t / h, and is dehydrated to a water content of 10 wt %, to obtain wastewater containing a small amount of organic matter and a concentrated liquid after dehydration;

[0076] After the wastewater is treated by the membrane separation device, the content of neopentyl glycol is 0.34wt%, the content of methanol is 0.52wt%, the content of isobutanol is 0.76wt%, the content of trimethylamine is 200ppm, and the water content is 97.82wt%;

[0077] The concentrate consists of 10 wt % water, and the organic matter content other than water includes: 81.45 wt % neopentyl glycol, 2.97 wt % methanol, 0.99 wt % trimethylamine, 0.96 wt % isobutyl alcohol, 0.4 wt % hydroxypivalic acid, and 0.78 wt % hydroxypivalic acid neopentyl glycol ester.

[0078] 2) The concentrated liquid enters a light-removing tower for distillation to remove light components. The actual number of plates of the light-removing tower is 30, the feed position is the 27th plate, the distillation operating pressure is 0.02 MPa, the temperature is 180° C., and the reflux ratio is 3; components with a lower boiling point than neopentyl glycol, such as methanol, isobutanol, trimethylamine and water, are removed from the top of the light-removing tower, and crude neopentyl glycol is obtained from the bottom of the tower;

[0079] The content of neopentyl glycol in the light components removed from the top of the light removal tower is 2 wt%;

[0080] The crude neopentyl glycol obtained in the bottom of the tower comprises: 97.93 wt % of neopentyl glycol, 0.89 wt % of hydroxypivalic acid, and 0.89 wt % of hydroxypivalic acid neopentyl glycol ester.

[0081] 3) The crude neopentyl glycol enters a hydrogenation system, and hydrogen is introduced into the system under the action of a hydrogenation catalyst for hydrogenation reaction. The hydrogenation catalyst comprises 35 wt% of copper oxide, 25 wt% of zinc oxide, 33 wt% of aluminum oxide and 7 wt% of manganese oxide. The residence time of the hydrogenation reaction is 60 min. The temperature of the hydrogenation reaction is 120° C., and the hydrogen pressure is 4.5 MPa to obtain a neopentyl glycol product.

[0082] The purity of the obtained neopentyl glycol product is 99.55 wt %.

[0083] The energy consumption per ton of neopentyl glycol production is 92 kg of standard coal, the butyraldehyde consumption per ton of neopentyl glycol product is 703 kg, and the acid value is 38 ppm (in terms of acetic acid).

[0084] Example 2

[0085] The neopentyl glycol reaction liquid comprises the following components in percentage by weight: 15.52 wt% water, 68.92 wt% neopentyl glycol, 6.72 wt% methanol, 1.01 wt% trimethylamine, 6.55 wt% isobutyl alcohol, 0.3 wt% hydroxypivalic acid, 0.6 wt% hydroxypivalic acid neopentyl glycol ester, 3000 ppm formic acid and 1500 ppm isobutyric acid.

[0086] Post-treatment method of neopentyl glycol reaction liquid:

[0087] 1) The neopentyl glycol reaction liquid enters the membrane separation device with a feed flow rate of 10 t / h, and is dehydrated to a water content of 0.02 wt%, to obtain wastewater containing a small amount of organic matter and a concentrated liquid after dehydration;

[0088] After the wastewater is treated by the membrane device, the content of neopentyl glycol is 0.52wt%, the content of methanol is 0.92wt%, the content of isobutanol is 1.76wt%, the content of trimethylamine is 220ppm, and the water content is 96.82wt%;

[0089] The concentrate has a water content of 0.02 wt %. In addition to water, the organic matter content includes: 91.45 wt % of neopentyl glycol, 2.67 wt % of methanol, 0.82 wt % of trimethylamine, 2.91 wt % of isobutyl alcohol, 0.35 wt % of hydroxypivalic acid, and 0.82 wt % of hydroxypivalic acid neopentyl glycol ester.

[0090] 2) The concentrated liquid enters a light component removal tower for distillation to remove light components. The actual number of plates of the light component removal tower is 20, the feed position is the 17th plate, the operating pressure is 0.05 MPa, the temperature is 200° C., and the reflux ratio is 4.9; components with a lower boiling point than neopentyl glycol, such as methanol, isobutanol, trimethylamine and water, are removed from the top of the light component removal tower, and crude neopentyl glycol is obtained from the bottom of the tower;

[0091] The content of neopentyl glycol in the light components removed from the top of the light removal tower is 1.2 wt%;

[0092] The crude neopentyl glycol obtained in the bottom of the tower comprises: 97.83 wt % of neopentyl glycol, 0.92 wt % of hydroxypivalic acid, and 0.98 wt % of hydroxypivalic acid neopentyl glycol ester.

[0093] 3) The crude neopentyl glycol enters a hydrogenation system, and hydrogen is introduced into the system under the action of a hydrogenation catalyst for hydrogenation reaction. The hydrogenation catalyst comprises 35 wt% of copper oxide, 25 wt% of zinc oxide, 33 wt% of aluminum oxide and 7 wt% of manganese oxide. The residence time of the hydrogenation reaction is 30 min. The temperature of the hydrogenation reaction is 100° C., and the hydrogen pressure is 4.0 MPa to obtain a neopentyl glycol product.

[0094] The purity of the obtained neopentyl glycol product is 99.59 wt %.

[0095] The energy consumption per ton of neopentyl glycol production is 88 kg of standard coal, the butyraldehyde consumption per ton of neopentyl glycol product is 710 kg, and the acid value is 35 ppm (in terms of acetic acid).

[0096] Example 3

[0097] The neopentyl glycol reaction liquid comprises the following components in percentage by weight: 45.02 wt% of water, 48.45 wt% of neopentyl glycol, 2.52 wt% of methanol, 1.01 wt% of trimethylamine, 1.65 wt% of isobutyl alcohol, 0.4 wt% of hydroxypivalic acid, 0.5 wt% of hydroxypivalic acid neopentyl glycol ester, 8000 ppm of formic acid, and 7000 ppm of isobutyric acid.

[0098] Post-treatment method of neopentyl glycol reaction liquid:

[0099] 1) The neopentyl glycol reaction liquid enters the membrane separation device with a feed flow rate of 15 t / h, and is dehydrated to a water content of 35 wt%, thereby obtaining wastewater containing a small amount of organic matter and a concentrated liquid after dehydration;

[0100] After the wastewater is treated by the membrane device, the content of neopentyl glycol is 0.25wt%, the content of methanol is 0.32wt%, the content of isobutanol is 0.46wt%, the content of trimethylamine is 109ppm, and the water content is 98.92wt%;

[0101] The concentrate consists of 35 wt% water, and the organic matter content other than water includes: 92.45 wt% neopentyl glycol, 2.27 wt% methanol, 0.12 wt% trimethylamine, 0.71 wt% isobutyl alcohol, 0.35 wt% hydroxypivalic acid, and 0.72 wt% hydroxypivalic acid neopentyl glycol ester.

[0102] 2) The concentrated liquid enters a light-removing tower for distillation to remove light components. The actual number of plates of the light-removing tower is 12, the feed position is the 10th plate, the distillation operating pressure is 0.008 MPa, the temperature is 120° C., and the reflux ratio is 2; components with a boiling point lower than that of neopentyl glycol, such as methanol, isobutanol, trimethylamine and water, are removed from the top of the light-removing tower, and crude neopentyl glycol is obtained from the bottom of the tower;

[0103] The content of neopentyl glycol in the light components removed from the top of the light removal tower is 0.72wt%;

[0104] The crude neopentyl glycol obtained in the bottom of the tower comprises: 97.55 wt % of neopentyl glycol, 0.58 wt % of hydroxypivalic acid, and 0.77 wt % of hydroxypivalic acid neopentyl glycol ester.

[0105] 3) The crude neopentyl glycol enters a hydrogenation system, and hydrogen is introduced into the system under the action of a hydrogenation catalyst for hydrogenation reaction. The hydrogenation catalyst comprises 35 wt% of copper oxide, 25 wt% of zinc oxide, 33 wt% of aluminum oxide and 7 wt% of manganese oxide. The residence time of the hydrogenation reaction is 13 min, the temperature of the hydrogenation reaction is 80° C., and the hydrogen pressure is 3.5 MPa to obtain a neopentyl glycol product.

[0106] The purity of the obtained neopentyl glycol product is 99.67 wt %.

[0107] The energy consumption per ton of neopentyl glycol production is 99 kg of standard coal, the butyraldehyde consumption per ton of neopentyl glycol product is 710 kg, and the acid value is 28 ppm (in terms of acetic acid).

[0108] Comparative Example 1

[0109] The neopentyl glycol reaction liquid of Example 1 is used, and the specific separation method steps are as follows: light components and water are removed according to the distillation separation operation of Example 1, the crude neopentyl glycol solution obtained in the bottom of the tower is subjected to secondary distillation separation to obtain a neopentyl glycol product from the top of the tower, and the heavy components in the bottom of the tower are incinerated.

[0110] The purity of the obtained neopentyl glycol product is 99.53 wt %.

[0111] The energy consumption per ton of neopentyl glycol production is 621 kg of standard coal, the butyraldehyde consumption per ton of neopentyl glycol product is 729 kg, and the acid value is 82 ppm (in terms of acetic acid).

[0112] Comparative Example 2

[0113] The method of Example 1 is referred to, except that the neopentyl glycol reaction solution is directly subjected to light removal treatment without removing water, that is, step 1) is omitted, and other operations and parameters remain unchanged to obtain a neopentyl glycol product.

[0114] The purity of the isolated neopentyl glycol product is 99.52 wt %.

[0115] The energy consumption per ton of neopentyl glycol production is 521 kg of standard coal, the butyraldehyde consumption per ton of neopentyl glycol product is 727 kg, and the acid value is 87 ppm (measured in acetic acid).

[0116] Comparative Example 3

[0117] The method of Example 1 is referred to, except that after the water is removed from the neopentyl glycol reaction solution, step 2) removing the light components is omitted, and other operations and parameters remain unchanged to obtain a crude neopentyl glycol product.

[0118] The purity of the separated neopentyl glycol product was 82.52 wt %, and no qualified product could be obtained.

[0119] Comparative Example 4

[0120] The method of Example 1 is referred to, except that the neopentyl glycol reaction liquid is directly subjected to post-hydrogenation treatment, i.e., the removal of water and light components is omitted, and other operations and parameters remain unchanged, to obtain a crude neopentyl glycol product.

[0121] The purity of the separated neopentyl glycol product was 62.51 wt %, and no qualified product could be obtained.

[0122] Comparative Example 5

[0123] The method of Example 1 is referred to, except that: the crude neopentyl glycol after removing water and light components by membrane separation and distillation is treated by distillation to remove heavy components, and the heavy components are incinerated to obtain the neopentyl glycol product.

[0124] The purity of the separated neopentyl glycol product is 99.53 wt %.

[0125] The energy consumption per ton of neopentyl glycol production is 341 kg of standard coal, the butyraldehyde consumption per ton of neopentyl glycol product is 720 kg, and the acid value is 80 ppm (in terms of acetic acid).

[0126] Comparative Example 6

[0127] The neopentyl glycol reaction liquid of Example 1 is used, and the specific separation method steps are as follows: light components and water are removed from the top of the tower by distillation separation, the crude neopentyl glycol solution obtained in the bottom of the tower is subjected to secondary distillation separation to obtain a neopentyl glycol product from the top of the tower, the heavy components in the bottom of the tower are subjected to tertiary distillation separation to obtain an NPG recovery product from the top of the tower, the NPG products of the secondary distillation and the tertiary distillation are mixed as the final product, and the residual liquid in the bottom of the tower is incinerated.

[0128] The purity of the isolated neopentyl glycol product is 99.50 wt%.

[0129] The energy consumption per ton of neopentyl glycol production is 620 kg of standard coal, the butyraldehyde consumption per ton of neopentyl glycol product is 715 kg, and the acid value is 82 ppm (in terms of acetic acid).

Claims

1. A post-treatment method for a neopentyl glycol reaction solution, characterized in that the steps include: (1) removing water and light components from the neopentyl glycol reaction solution to obtain crude neopentyl glycol; (2) The crude neopentyl glycol is subjected to hydrogenation reaction to obtain a neopentyl glycol product.

2. The post-processing method according to claim 1, characterized in that: The neopentyl glycol reaction liquid in step (1) is a neopentyl glycol hydrogenation reaction liquid.

3. The post-processing method according to claim 2, characterized in that: The mass percentage composition of the neopentyl glycol reaction liquid includes 30-70wt% of neopentyl glycol, 10-50wt% of water, 1-10wt% of methanol, 1-10wt% of isobutanol, 0.01-3wt% of trimethylamine, 10-10000ppm of formic acid, 10-10000ppm of isobutyric acid, 10-10000ppm of hydroxypivalic acid, 10-10000ppm of hydroxypivalic acid neopentyl glycol ester and other trace impurities.

4. The post-processing method according to claim 1, characterized in that: The water in step (1) is removed by membrane separation; Preferably, the type of the membrane in the membrane separation method is one or a combination of two or more of an organic molecular sieve membrane and an inorganic molecular sieve membrane, more preferably an inorganic molecular sieve membrane.

5. The post-processing method according to claim 1, characterized in that: Step (1) The neopentyl glycol reaction solution is dehydrated to a water content of 0 to 50 wt %, preferably 10 to 35 wt %.

6. The post-processing method according to claim 1, characterized in that: The light components in step (1) are removed by distillation; Preferably, the distillation operation has a pressure of 0.006-0.05 MPa, preferably 0.01-0.04 MPa, and a temperature of 50-200°C, preferably 120-190°C.

7. The post-processing method according to claim 1, characterized in that: The hydrogenation reaction in step (2) comprises adding a hydrogenation catalyst to the reaction system; Preferably, the hydrogenation catalyst is selected from one or more copper-based hydrogenation catalysts.

8. The post-processing method according to claim 7, characterized in that: The copper-based hydrogenation catalyst contains three metal elements of copper, zinc and aluminum, or contains four metal elements of copper, zinc, aluminum and manganese, and more preferably contains four metal elements of copper, zinc, aluminum and manganese.

9. The post-processing method according to claim 8, characterized in that: The copper-based hydrogenation catalyst containing four metal elements of copper, zinc, aluminum and manganese comprises 20-50wt% of copper oxide, 20-40wt% of zinc oxide, 20-40wt% of aluminum oxide and 1-10wt% of manganese oxide in weight percentage, preferably 30-40wt% of copper oxide, 25-35wt% of zinc oxide, 25-35wt% of aluminum oxide and 5-10wt% of manganese oxide.

10. The post-processing method according to claim 1, characterized in that: The conditions of the hydrogenation reaction in step (2) are: reaction temperature of 80-120° C., hydrogen pressure of 3.0-4.5 MPa, and reaction time of 10-60 min.