阅读说明：本技术 一种煤或煤液化残渣水热氧化生产高附加值羧酸的方法 (Method for producing high value-added carboxylic acid by hydrothermal oxidation of coal or coal liquefaction residues ) 是由 丛兴顺 李敏 刘春丽 亓欣 王登峰 石铁生 李龙 孔雪 姚敏绮 魏倩 张学斌 于 2020-12-21 设计创作，主要内容包括：一种煤或煤液化残渣水热氧化生产高附加值羧酸的方法,包括如下步骤：提供煤或者煤液化残渣作为底物；将底物与水混合置于反应釜中,并将与反应釜分离设置的用于储存氧化剂的储液腔与反应釜连通设置；然后将反应釜温度升温至70-180℃以上,在搅拌状态下,将氧化剂滴加到底物当中,反应时间为0.2-1.5小时,得到氧化底物；将氧化底物进行过滤分离得到羧酸产物。本发明采用反应釜为反应容器,将反应样品与氧化剂分开,创新性地提出了水热氧化技术,在水热条件下,利用恒压滴液原理逐滴添加氧化剂,加快了反应速度,显著缩短反应时间,提高了氧化效率,将整体的环境由氧化性反应环境改为还原性反应环境,降低了产品过氧化问题,节约了资源。(A method for producing high value-added carboxylic acid by coal or coal liquefaction residue through hydrothermal oxidation comprises the following steps: providing coal or coal liquefaction residue as a substrate; mixing a substrate and water, placing the mixture in a reaction kettle, and communicating a liquid storage cavity which is separated from the reaction kettle and used for storing an oxidant with the reaction kettle; then heating the temperature of the reaction kettle to be more than 70-180 ℃, dropwise adding an oxidant into the substrate under the stirring state, and reacting for 0.2-1.5 hours to obtain an oxidation substrate; and filtering and separating the oxidation substrate to obtain the carboxylic acid product. The invention adopts the reaction kettle as a reaction vessel, separates a reaction sample from an oxidant, innovatively provides a hydrothermal oxidation technology, and adds the oxidant dropwise by using a constant-pressure dropping liquid principle under a hydrothermal condition, thereby quickening the reaction speed, obviously shortening the reaction time, improving the oxidation efficiency, changing the whole environment from an oxidative reaction environment into a reductive reaction environment, reducing the product peroxidation problem and saving resources.)

1. A method for producing carboxylic acid with high added value by hydrothermal oxidation of coal or coal liquefaction residues is characterized in that: the method comprises the following steps:

providing coal or coal liquefaction residue as a substrate;

mixing a substrate and water, placing the mixture in a reaction kettle, and communicating a liquid storage cavity which is separated from the reaction kettle and used for storing an oxidant with the reaction kettle;

then heating the temperature of the reaction kettle to be more than 70-180 ℃, dropwise adding an oxidant into the substrate under the stirring state, and reacting for 0.2-1.5 hours to obtain an oxidation substrate;

and filtering and separating the oxidation substrate to obtain the carboxylic acid product.

2. The method for producing high value-added carboxylic acid by hydrothermal oxidation of coal or coal liquefaction residue as claimed in claim 1, wherein: the reaction kettle comprises an oxidation cavity and a temperature regulator which is matched with the oxidation cavity, a stirrer is arranged in the oxidation cavity, the oxidation cavity is sealed, a liquid storage cavity is communicated with the oxidation cavity, a liquid space of the liquid storage cavity is communicated with the oxidation cavity through a liquid leading-in pipeline, a gas space of the liquid storage cavity is communicated with the oxidation cavity through a pressure balance pipe, and a controller used for adjusting the flow is arranged on the liquid leading-in pipeline.

3. The method for producing high value-added carboxylic acid by hydrothermal oxidation of coal or coal liquefaction residue as claimed in claim 2, wherein: the oxidation chamber comprises a U-shaped groove body, the middle of the U-shaped groove body forms the oxidation chamber, a plurality of handles are arranged at the bottom of the U-shaped groove body, a kettle cover is arranged on the U-shaped groove body, and the kettle cover is fixedly connected with the U-shaped groove body through a plurality of connecting bolts.

4. The method for producing high value-added carboxylic acid by hydrothermal oxidation of coal or coal liquefaction residue as claimed in claim 2, wherein: the temperature regulator comprises a temperature adjusting coil pipe arranged in the oxidation cavity, and two ends of the temperature adjusting coil pipe are respectively arranged through the cavity wall of the oxidation cavity; a heating cavity is also arranged at the outer side of the oxidation cavity, and the heating cavity is wrapped at the outer side of the oxidation cavity; the liquid storage cavity is arranged above the oxidation cavity, and the liquid leading-in pipeline and the pressure balance pipe are communicated with the gas space in the oxidation cavity; the controller is a flow control valve; the flow control valve is a constant-pressure constant-speed dropping valve; a thermocouple sleeve for inserting a thermocouple is also arranged in the oxidation cavity; the pressure gauge is communicated with the oxidation cavity; the liquid storage cavity is provided with a feed inlet, and a sealing plug is arranged on the feed inlet in a sealing manner.

5. The method for producing high value-added carboxylic acid by hydrothermal oxidation of coal or coal liquefaction residue as claimed in claim 1, wherein: the filtration separation is carried out according to the following method: filtering the oxidation substrate to obtain a first filtrate, adjusting the pH value of the first filtrate to 1-5, filtering again to obtain a second filtrate, extracting the second filtrate with an organic solvent, taking an extraction liquid, and removing the solvent in the extraction liquid by means of thermal evaporation to obtain the carboxylic acid.

6. The method for producing high value-added carboxylic acid by hydrothermal oxidation of coal or coal liquefaction residue as claimed in claim 1, wherein: and (3) dewatering the extract liquor, and then removing the solvent by rotary evaporation to obtain the carboxylic acid.

7. The method for producing high value-added carboxylic acid by hydrothermal oxidation of coal or coal liquefaction residue as claimed in claim 5, wherein: the organic solvent is petroleum ether and/or chloroform and/or dichloromethane and/or benzene and/or toluene and/or ethyl acetate and/or diethyl ether and/or cyclohexanone.

8. The method for producing high value-added carboxylic acid by hydrothermal oxidation of coal or coal liquefaction residue as claimed in claim 7, wherein: the extraction process is single-stage extraction or fractional extraction.

9. The method for producing high value-added carboxylic acid by hydrothermal oxidation of coal or coal liquefaction residue as claimed in claim 1, wherein: the carboxylic acid is esterified and then subjected to gas chromatography/mass spectrometry.

10. The method for producing high value-added carboxylic acid by hydrothermal oxidation of coal or coal liquefaction residue as claimed in claim 9, wherein: the esterification reactant adopted by the carboxylic acid esterification is diazomethane or methanol or a methanol solution of boron trifluoride.

Technical Field

The application relates to a method for producing high value-added carboxylic acid by hydrothermal oxidation of coal or coal liquefaction residues.

Background

Coal oxidation is an important method for producing carboxylic acid, especially high value-added benzenepolycarboxylic acid, and a large number of researchers have conducted research experiments, but in order to achieve the purpose of oxidation and avoid causing uncontrollable oxidation process, currently researched coal solid-liquid oxidation reaction is mostly conducted below 50 ℃, due to low reaction temperature, added oxidant reacts slowly, reaction time is long, generally more than 12 hours, and in addition, a large amount of unreacted oxidant can cause oxidation environment in a reaction kettle, so that carboxylic acid products are over oxidized, and yield of oxidation products is reduced. After the oxidation reaction starts, the temperature in the reaction kettle can rise due to the heat released by the reaction, so that the oxidation reaction is accelerated and repeated, and thermal runaway and even explosion accidents are easily caused.

The preparation of liquid fuel by coal liquefaction is an important method for relieving the shortage of petroleum and also an extremely important strategic technology, about 20% of liquefaction residues are produced in the coal liquefaction process, the residues have high ash content and high carbon content, the treatment of the coal liquefaction residues is difficult at present, but the condensation degree of aromatic rings usually contained in the coal liquefaction residues is high, the aromatic rings are important raw materials for preparing aromatic polycarboxylic acid, and the normal temperature oxidation of the aromatic rings has the problem of similar coal oxidation.

The existing normal-temperature oxidation method for coal and liquefaction residues has the problems of long reaction time, easy peroxidation of products and difficult control of reaction. The prior art does not address this.

Disclosure of Invention

In order to solve the problems, the application provides a method for producing high value-added carboxylic acid by hydrothermal oxidation of coal or coal liquefaction residues, which comprises the following steps: providing coal or coal liquefaction residue as a substrate; mixing a substrate and water, placing the mixture in a reaction kettle, and communicating a liquid storage cavity which is separated from the reaction kettle and used for storing an oxidant with the reaction kettle; then heating the temperature of the reaction kettle to be more than 70-180 ℃, dropwise adding an oxidant into the substrate under the stirring state, and reacting for 0.2-1.5 hours to obtain an oxidation substrate; and filtering and separating the oxidation substrate to obtain the carboxylic acid product. The invention adopts the reaction kettle as a reaction vessel, separates a reaction sample from an oxidant, innovatively provides a hydrothermal oxidation technology, and adds the oxidant dropwise by using a constant-pressure dropping liquid principle under a hydrothermal condition, thereby quickening the reaction speed, obviously shortening the reaction time, improving the oxidation efficiency, changing the whole environment from an oxidative reaction environment into a reductive reaction environment, reducing the product peroxidation problem and saving resources.

Preferably, reation kettle includes the oxidation chamber and with the temperature regulator that the cooperation of oxidation chamber set up, is equipped with the agitator in the oxidation chamber, the oxidation chamber seals the setting, and stock solution chamber and oxidation chamber intercommunication set up, and the liquid space in stock solution chamber passes through liquid inlet pipe and oxidation chamber intercommunication setting, and stock solution chamber gas space passes through pressure balance pipe and oxidation chamber intercommunication setting, is equipped with the controller that is used for regulating flow on the liquid inlet pipe. Preferably, the oxidation chamber includes the U-shaped cell body, and the middle part of U-shaped cell body forms the oxidation chamber, is equipped with a plurality of handles in the bottom of U-shaped cell body, is equipped with the kettle cover on the U-shaped cell body, the kettle cover links firmly the setting through a plurality of connecting bolt and U-shaped cell body. This application will oxidize and set up temperature regulator in order to cool off or heat the oxidation chamber on the chamber, and the stock solution chamber then is in order to deposit the oxidant alone, then makes its internal pressure and the pressure balance who receives the oxidation chamber through the pressure balance pipe to carry out the speed that the oxidant lets in through the controller, thereby can carry out reasonable control to the process of oxidation.

Preferably, the temperature regulator comprises a temperature adjusting coil pipe arranged in the oxidation cavity, and two ends of the temperature adjusting coil pipe are respectively arranged through the cavity wall of the oxidation cavity; a heating cavity is also arranged at the outer side of the oxidation cavity, and the heating cavity is wrapped at the outer side of the oxidation cavity; the liquid storage cavity is arranged above the oxidation cavity, and the liquid leading-in pipeline and the pressure balance pipe are communicated with the gas space in the oxidation cavity; the controller is a flow control valve; the flow control valve is a constant-pressure constant-speed dropping valve; a thermocouple sleeve for inserting a thermocouple is also arranged in the oxidation cavity; the pressure gauge is communicated with the oxidation cavity; the liquid storage cavity is provided with a feed inlet, and a sealing plug is arranged on the feed inlet in a sealing manner. This application is through setting up the stock solution chamber at the setting in oxidation chamber to carry out the balanced setting with the pressure of gas one side, place the oxidation liquid in the stock solution chamber under the effect of gravity and flow control valve's regulating action down flow into the oxidation intracavity according to certain speed.

Preferably, the filtration separation is carried out according to the following method: filtering the oxidation substrate to obtain a first filtrate, adjusting the pH value of the first filtrate to 1-5, filtering again to obtain a second filtrate, extracting the second filtrate with an organic solvent, taking an extraction liquid, and removing the solvent in the extraction liquid by means of thermal evaporation to obtain the carboxylic acid.

Preferably, the extract is subjected to water removal, and after the water removal, the solvent is removed by rotary evaporation to obtain the carboxylic acid.

Preferably, the organic solvent is petroleum ether and/or chloroform and/or dichloromethane and/or benzene and/or toluene and/or ethyl acetate and/or diethyl ether and/or cyclohexanone.

Preferably, the extraction process is a single stage extraction or a staged extraction.

Preferably, the carboxylic acid is esterified prior to gas chromatography/mass spectrometry.

Preferably, the esterification reactant for carboxylic acid esterification is diazomethane or methanol or a methanol solution of boron trifluoride.

This application can bring following beneficial effect:

1. the reaction kettle is used as a reaction container, a reaction sample is separated from an oxidant, a hydrothermal oxidation technology is innovatively provided, the oxidant is added dropwise by using a constant-pressure dropping liquid principle under a hydrothermal condition, the reaction speed is accelerated, the reaction time is obviously shortened, the oxidation efficiency is improved, the whole environment is changed from an oxidative reaction environment to a reductive reaction environment, the product peroxidation problem is reduced, and resources are saved;

2. according to the device, the temperature regulator is arranged on the oxidation cavity to cool or heat the oxidation cavity, the liquid storage cavity is used for storing the oxidant independently, the internal pressure of the liquid storage cavity is balanced with the pressure of the oxidation cavity through the pressure balance pipe, and the rate of introducing the oxidant is controlled through the controller, so that the oxidation process can be reasonably controlled;

3. this application is through setting up the stock solution chamber at the setting in oxidation chamber to carry out the balanced setting with the pressure of gas one side, place the oxidation liquid in the stock solution chamber under the effect of gravity and flow control valve's regulating action down flow into the oxidation intracavity according to certain speed.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

fig. 1 is a schematic structural diagram of the present application.

Detailed Description

In order to clearly explain the technical features of the present invention, the present application will be explained in detail by the following embodiments in combination with the accompanying drawings.

As shown in the drawings, the following detailed description is given by way of example in order to more clearly explain the overall concept of the present application.

In addition, in the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", and the like, indicate orientations and positional relationships based on those shown in the drawings, are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present application.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; the connection can be mechanical connection, electrical connection or communication; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

In a first embodiment, introduce the reation kettle that this application used, as shown in fig. 1, a coal or coal liquefaction residue hydrothermal oxidation produces high added value carboxylic acid's method, including oxidation chamber 1 and with the temperature regulator of oxidation chamber 1 cooperation setting, be equipped with agitator 2 in oxidation chamber 1, oxidation chamber 1 seals the setting, and oxidation chamber 1 sets up with the cooperation of stock solution chamber 3, and the liquid space of stock solution chamber 3 sets up with oxidation chamber 1 intercommunication through liquid inlet line 4, and 3 gas spaces in stock solution chamber set up with oxidation chamber 1 intercommunication through pressure balance pipe 5, are equipped with the controller that is used for adjusting the flow on liquid inlet line 4. The oxidation chamber 1 comprises a U-shaped groove body 6, the oxidation chamber 1 is formed in the middle of the U-shaped groove body 6, a plurality of handles 7 are arranged at the bottom of the U-shaped groove body 6, a kettle cover 8 is arranged on the U-shaped groove body 6, and the kettle cover 8 is fixedly connected with the U-shaped groove body 6 through a plurality of connecting bolts 9. The temperature regulator comprises a temperature adjusting coil 10 arranged in the oxidation cavity 1, and two ends of the temperature adjusting coil 10 respectively penetrate through the cavity wall of the oxidation cavity 1. The outer side of the oxidation cavity 1 is also provided with a heating cavity 11, and the heating cavity 11 is wrapped outside the oxidation cavity. The liquid storage cavity 3 is arranged above the oxidation cavity 1, and the liquid leading-in pipeline and the pressure balance pipe 5 are communicated with the gas space in the oxidation cavity 1. The controller is a flow control valve 12. The flow control valve 12 is a constant pressure and constant speed dropping valve. A thermowell 13 for inserting a thermocouple is also provided in the oxidation chamber 1. And a pressure gauge 14 communicated with the oxidation cavity 1. The liquid storage cavity is provided with a feed inlet 15, and a sealing plug 16 is hermetically arranged on the feed inlet 15.

When the device is used, a substrate to be oxidized, such as coal, biomass and other substances, is placed in an oxidation cavity 1, then a kettle cover 8 is used for sealing, an oxidant is placed in a liquid storage cavity 3 through a feed inlet, then the feed inlet is plugged through a sealing plug, then the temperature of the oxidation cavity 1 is controlled under a specified condition through the synergistic effect of a temperature adjusting coil 10 and a heating cavity 11, in the process, the oxidant is dripped in a controlled manner under the action of a liquid introduction pipeline and a flow control valve 12 on the oxidant, and in the process, the temperature of the oxidation cavity 1 is still controlled through the temperature adjusting coil 10 and the heating cavity 11, so that the controllability of the oxidation process is realized until the reaction is finished.

The parts in contact with the oxidation cavity 1 generally need to adopt corrosion-resistant parts, such as pure titanium materials, 316 stainless steel and 304 stainless steel with a polytetrafluoroethylene lining, and the kettle cover can be hermetically connected with the U-shaped groove body in a line sealing manner, and is resistant to pressure of 10MPa and temperature of 200 ℃; the requirement of temperature control precision is generally +/-1 ℃; the stirrer may be a mechanical stirrer, but may be a magnetic stirrer.

In a second example, a reactor as in example 1 was used, comprising the following steps:

s1, sample loading: crushing the victory lignite to 200 meshes, putting 1g of a coal sample into a novel efficient reaction kettle, adding 15mL of water, adding 25mL of sodium hypochlorite aqueous solution into a liquid storage tank, and sealing the reaction kettle.

S2, hydrothermal oxidation: starting magnetic stirring, heating the reaction kettle to 120 ℃, dropwise adding sodium hypochlorite in the liquid storage tank into the reaction kettle within 20 minutes, reacting for 5 minutes after dropwise adding, and cooling to obtain a reaction mixture.

S3, filtering and separating: and (3) filtering and separating the reaction mixture obtained in the step S2 to obtain a filtrate, adjusting the pH value of the filtrate to be neutral, filtering again to remove humic acid to obtain a carboxylic acid aqueous solution, adjusting the solution to be 1, adding the solution into a 100mL separating funnel, extracting for 10 times by using 50mL ethyl acetate, combining the extracts, dehydrating by using anhydrous sodium sulfate, and removing the solvent by rotary evaporation to obtain 0.3g of a carboxylic acid product.

S4, product composition analysis: and (3) carrying out structural identification on the carboxylic acid product obtained in the S3 by using gas chromatography/mass spectrometry after diazomethane esterification. The oxidation sample mainly contains benzene polycarboxylic acid, accounting for about 80%, wherein benzene tricarboxylic acid and benzene tetracarboxylic acid are contained in a large amount; secondly, aliphatic carboxylic acid and a small amount of dibenzoic acid.

For comparison, in S2, a normal temperature reaction was performed to obtain 0.1g of the final carboxylic acid product;

if sodium hypochlorite is completely mixed with coal in S1, 0.16g of the carboxylic acid product is obtained in the case of the second hydrothermal oxidation, and 0.07g of the carboxylic acid product is obtained in the case of the second hydrothermal oxidation.

In a third example, a reactor as in example 1 was used, comprising the following steps:

s1, sample loading: crushing the coal liquefaction residues to 200 meshes, putting 1g of the crushed coal liquefaction residues into a novel efficient reaction kettle, adding 15mL of water, adding 15mL of sodium hypochlorite aqueous solution into a liquid storage tank, and sealing the reaction kettle.

S2, hydrothermal oxidation: starting magnetic stirring, heating the reaction kettle to 110 ℃, dropwise adding sodium hypochlorite in the liquid storage tank into the reaction kettle within 10 minutes, reacting for 5 minutes after dropwise adding, and cooling to obtain a reaction mixture.

S3, filtering and separating: and (3) filtering and separating the reaction mixture obtained in the step S2 to obtain a filtrate, adjusting the pH value of the filtrate to be neutral, filtering again to remove humic acid to obtain a carboxylic acid aqueous solution, adjusting the solution to be 1, adding the solution into a 100mL separating funnel, extracting for 10 times by using 50mL diethyl ether, combining the extracts, dehydrating by using anhydrous sodium sulfate, and removing the solvent by rotary evaporation to obtain 0.19g of a carboxylic acid product.

S4, product composition analysis: and (3) carrying out structural identification on the carboxylic acid product obtained in the S3 by using gas chromatography/mass spectrometry after diazomethane esterification. The oxidation product mainly contains benzene polycarboxylic acid which accounts for about 80 percent, and also contains a small amount of biphenyl polycarboxylic acid.

For comparison, the carboxylic acid product obtained in S2 by the normal temperature reaction was 0.06 g;

if sodium hypochlorite is completely mixed with the residue in S1, 0.08g of the carboxylic acid product is obtained in the case of the second hydrothermal oxidation, and 0.03g of the carboxylic acid product is obtained in the case of the second hydrothermal oxidation.

In addition, it should be noted that: the conditions for structural identification are as follows: the temperature of a chromatographic column incubator is raised from 60 ℃ to 350 ℃ at the rate of 4 ℃/min, the temperature is kept constant for 30 min at 350 ℃, an ionization source is bombarded by electrons, a quadrupole mass analyzer is used, and the scanning range is m/z 33-750. The molecular ion peak of methylparaben was barely visible as [ M-31]⁺Is a base peak; the molecular ion peak intensity of the methyl dibenzoate is very low and is slightly visible to be [ M-31 ]]⁺Is a basic peak and has obvious [ (M-62)/2 ]]⁺The double charge ion peak, which appears as a single peak in the quadrupole mass spectrum, is hardly visible as the molecular ion peak of methylparaben [ M-59 ]]⁺Is a basic peak and has stronger [ M-31 ]]⁺Peak(s).

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.