Method for preparing nitrosyl sulfuric acid
By using nitric oxide and mixed acid to react instead of the traditional sulfur dioxide reduction method, nitrosyl sulfuric acid is prepared, which solves the problems of high raw material costs and production safety hazards, and achieves an efficient and safe production process.
Patent Information
- Application Number
- CN202311608797.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-29
- Publication Date
- 2025-05-30
AI Technical Summary
In the traditional preparation method of nitrosylsulfuric acid, the use of sulfur dioxide reduction method leads to high raw material costs, complex production process and safety hazards.
Nitric oxide (NO) is used instead of sulfur dioxide as a reducing agent to react with mixed acid to produce nitrosyl sulfuric acid, which reduces the consumption of nitric acid and reduces the cost of raw materials. It also exotherms less heat during the reaction and has a stable pressure, which improves production safety.
It achieves the reduction of raw material costs, improves reaction efficiency, reduces heat exogenousness, ensures the safety of the production process, and avoids the problem of by-production of sodium salt in traditional methods.
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of chemical synthesis, relates to the preparation of nitrosyl sulfuric acid, and particularly relates to a method for preparing nitrosyl sulfuric acid with reduced raw material costs, stable pressure, and high production safety. Background Art
[0002] Nitrosyl sulfuric acid is used in reactions such as azo dye pigment synthesis, caprolactam synthesis, and nitrosation, and is an important bulk chemical raw material. In traditional dye production, it is prepared by reacting sodium nitrite with sulfuric acid. This method results in a relatively low concentration of nitrosyl sulfuric acid and by-produces sodium salts, which is a non-environmentally friendly process. Currently, in the dye industry, the method of reducing nitric acid in mixed acid with sulfur dioxide (SO 2 ) is commonly used, that is, 1 mol of SO 2 reacts with 1 mol of nitric acid to produce 1 mol of nitrosyl sulfuric acid. The reaction formula is SO 2 +HNO 3 =NOHSO 4 , and the SO 2 used is generally a liquid in steel cylinders. The industrial preparation method of liquid SO 2 includes the pure oxygen method, the sodium citrate method, and the amino acid method. After extraction, it is dried, compressed, condensed, and canned to obtain the finished product. The production process of liquid SO 2 is complex and costly. After reducing nitric acid, it is converted into sulfuric acid with a low price. Therefore, the cost of nitrosyl sulfuric acid prepared by the SO 2 reduction method is high.
[0003] Compared with sulfur dioxide, nitrogen monoxide (NO) has more sources and lower costs. NO can come from the oxidation reaction of ammonia and oxygen or air, that is, the front end of nitric acid preparation. NO can also come from the flue gas of high-temperature combustion, and the main nitrogen oxides in it are NO. NO can also come from the waste gas generated by the reaction of nitric acid as an oxidant. NO cannot be absorbed by acids such as sulfuric acid and hydrochloric acid, nor can it be absorbed by alkalis such as sodium hydroxide, potassium hydroxide, and calcium hydroxide. Although NO can easily react with oxygen to form NO 2 that can be absorbed by alkali solution, due to the reversibility of the reaction, it is difficult to be completely converted due to the influence of temperature and pressure. Nitric oxide gas has always been a difficult problem in waste gas treatment. Absorbing NO with mixed acid can not only be used as a method for preparing nitrosyl sulfuric acid but also as a method for treating NO waste gas. Summary of the Invention
[0004] To solve the above problems, the present invention provides a method for preparing nitrosyl sulfuric acid. The present invention uses NO instead of SO 2 as a reducing agent, does not consume SO 2 , and reduces the consumption of nitric acid, greatly reducing the raw material cost. At the same time, the heat released during the reaction is less, the pressure during the reaction is stable, there is no sudden pressure rise phenomenon, and the production safety is high.
[0005] To achieve the above object, the present invention adopts the following technical solutions:
[0006] The present invention provides a method for preparing nitrosylsulfuric acid. The method includes reacting a mixed acid with a gas containing nitric oxide to generate nitrosylsulfuric acid. The gas containing nitric oxide is from ammonia oxidation products, nitric acid oxidation waste gas or combustion waste gas. The mass concentration of the end product nitrosylsulfuric acid is 1-60%. The reaction equation is: 2NO + HNO 3 + 3H 2 SO 4 =3NOHSO 4 + 2H 2 O.
[0007] As a preferred embodiment of the present invention, the gas containing nitric oxide is a single nitric oxide gas or a mixed gas of nitric oxide and one or more of NO 2 , N 2 O 3 , SO 2 , SO 3 , O 2 , H 2 , N 2 , CO 2 , CO.
[0008] In the "gas containing nitric oxide", in addition to containing NO, it may also contain one or more of the gases NO 2 , N 2 O 3 , SO 2 , SO 3 , O 2 , H 2 , N 2 , CO 2 , CO. Due to the influence of the source, the nitric oxide gas may contain these gases. O 2 will react with NO to generate NO 2 , and then be absorbed by sulfuric acid to generate nitrosylsulfuric acid and nitric acid. SO 2 reacts with nitric acid in the mixed acid to generate nitrosylsulfuric acid. SO 3 is absorbed by the mixed acid to generate sulfuric acid. N 2 and CO 2 gases will not be absorbed by the mixed acid and have no influence on the product. Therefore, the situation where the gas containing nitric oxide is mixed with these gases is also within the scope of the present invention.
[0009] Exemplary NO comes from an NO cylinder with a content greater than 90%. Exemplary NO is an ammonia oxidation product, in which the main nitrogen oxides are NO, and it also contains NO 2, O 2 , H 2 O, and N 2 ; Exemplary NO comes from the waste gas of the nitric acid oxidation reaction, where the amount of NO is not less than the amount of NO 2 , and it also contains H 2 O, O 2 , N 2 ; Exemplary NO comes from the waste gas of boiler combustion, which in addition to containing NO, also contains NO 2 , O 2 , H 2 O, N 2 , SO 2 , SO 3 and CO 2 .
[0010] As a preferred embodiment of the present invention, in the gas containing nitric oxide, the amount of substance of nitric oxide M NO and the sum of twice the amount of substance of sulfur dioxide Mso 2 are greater than the amount of substance of nitrogen dioxide M NO2 , that is, M NO + 2Mso 2 > M NO2 .
[0011] To ensure that all the nitric acid in the mixed acid can be converted and finally obtain a qualified nitrosylsulfuric acid product, the method of the present invention requires that the amount of reducing agent in the nitric oxide gas exceeds the amount of oxidizing agent. Exemplary NO volume fraction is 90 - 99%, N 2 volume fraction is 5 - 10%; Exemplary nitric oxide gas has a NO volume fraction of 6 - 10%, NO 2 volume fraction of 0.5 - 3%, N 2 volume fraction of 78 - 82%, O 2 volume fraction of 0.2 - 3%; Exemplary nitric oxide gas has a NO volume fraction of 55 - 99%, NO 2 volume fraction of 1 - 45%.
[0012] As a preferred embodiment of the present invention, the ammonia oxidation product is prepared by reacting ammonia with air or oxygen, and then reacting with the mixed acid to prepare nitrosylsulfuric acid.
[0013] As a preferred embodiment of the present invention, the molar ratio of ammonia to oxygen is 1:1.2 - 1:2.0.
[0014] As a preferred embodiment of the present invention, when the gas containing nitric oxide reacts with the mixed acid, the gas pressure is 0.05 - 3.0 Mpa.
[0015] More preferably, the gas pressure of the gas containing nitric oxide is 0.10 - 0.30 MPa.
[0016] As a preferred embodiment of the present invention, in the mixed acid, the mass percentage of sulfuric acid is 60-99%, the mass percentage of nitric acid is 0.1-11%, the mass percentage of water is 0-30%, and the mass percentage of nitrosylsulfuric acid is 0-55%.
[0017] As a preferred embodiment of the present invention, the sulfuric acid includes fuming sulfuric acid.
[0018] Since water is generated when NO reduces nitric acid during the reaction, when it is necessary to maintain a high-concentration sulfuric acid system, the present invention uses fuming sulfuric acid to prepare the mixed acid, and uses the sulfur trioxide therein to eliminate part of the generated water, so as to keep the concentration of sulfuric acid in the system from decreasing.
[0019] During the process of NO reducing nitric acid, the amount of nitrosylsulfuric acid gradually increases and the amount of nitric acid gradually decreases until the nitric acid disappears at the end of the reaction. Therefore, the reaction of the solution formed by nitrosylsulfuric acid, nitric acid, water and sulfuric acid with NO is also within the scope of the claimed rights of this patent. In the exemplary mixed acid, the mass fraction of sulfuric acid is 85-95%, the mass fraction of water is 2%, and the mass fraction of nitric acid is 3-10%; in the exemplary mixed acid, the mass fraction of sulfuric acid is 75-85%, the mass fraction of water is 14.5%, and the mass fraction of nitric acid is 0.5-10%; in the exemplary mixed acid, the mass fraction of sulfuric acid is 55-75%, the mass fraction of water is 2-20%, the mass fraction of nitric acid is 0.5-5%, and the mass fraction of nitrosylsulfuric acid is 5-30%.
[0020] As a preferred embodiment of the present invention, the temperature during the reaction is -10°C to 140°C, and the temperature at the end of the reaction is 20°C - 80°C. The end of the reaction is that the solution changes from colorless or light yellow to blue-black or blue-green.
[0021] A high reaction process temperature is beneficial to improving the heat exchange efficiency, and the highest reaction temperature can reach 140°C. To avoid product decomposition and ensure reaction safety, the temperature is reduced to 20-80°C before the end of the reaction, and the final discharge temperature is preferably 20-60°C.
[0022] As a preferred embodiment of the present invention, the reaction includes a batch reaction or a continuous flow reaction.
[0023] When a batch reaction is adopted, the gas containing nitric oxide passes through 2-6 reaction kettles in sequence;
[0024] When a continuous flow reaction is adopted, the continuous flow reaction is a multi-kettle series countercurrent reaction or a packed tower reaction or a tray tower reaction.
[0025] Compared with the prior art, the present invention has the following beneficial effects:
[0026] 1) The present invention does not use SO 2 , saving raw material costs.
[0027] 2) The reaction efficiency of the present invention is high and the heat release is small. In the present invention, two parts of NO reduce one part of HNO 3 , and only 2 / 3 mol of electrons need to be transferred for each preparation of 1 mol of nitrosylsulfuric acid, while 2 the SO method requires the transfer of 2 mol of electrons.
[0028] 3) The raw material cost of the present invention is low. NO is a common component in the waste gas of chemical plants producing or using nitric acid and sodium nitrite. Using it to prepare nitrosylsulfuric acid turns waste into treasure and has good economic benefits. Preparing NO by ammonia oxidation is also a very mature technology and the cost is lower than that of nitric acid.
[0029] 4) The reaction rate of the present invention is fast, the pressure is stable, and the production safety is high. When preparing nitrosylsulfuric acid by the liquid SO 2 reduction method, if the gasification is unstable and the liquid directly enters the reaction kettle, it will cause intense heat release and sudden pressure rise, posing a safety hazard. However, the NO method does not have such problems. Detailed implementation mode
[0030] In order to make the technical means, creative features, achieved purposes and functions of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments. However, the following embodiments are only the preferred embodiments of the present invention, not all of them. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative labor all belong to the protection scope of the present invention. The experimental methods in the following embodiments are all conventional methods unless otherwise specified, and the materials, reagents, etc. used in the following embodiments can be obtained from commercial channels unless otherwise specified.
[0031] The content described below represents the mass fraction of pure nitrosylsulfuric acid in the nitrosylsulfuric acid product.
[0032] Example 1
[0033] In a 1 L reactor, 870 g of 98% sulfuric acid and 67.5 g of 98% nitric acid were added. Stirring was started, and NO gas was slowly introduced into the mixed acid. The pressure was controlled at 0.15 - 0.20 MPa, and the reaction temperature was 60 - 70°C. When the solution turned blue, the gas supply was stopped, and the temperature was lowered and the product was discharged to obtain a nitrosylsulfuric acid product with a content of 39.5%.
[0034] Example 2
[0035] In a 1 L reactor, 918 g of 98% sulfuric acid and 42 g of 98% nitric acid were added. Stirring was started, and NO gas was slowly introduced into the mixed acid. The reaction temperature was controlled at 60 - 70°C. When the solution turned blue, the gas supply was stopped, and the temperature was lowered and the product was discharged to obtain a nitrosylsulfuric acid product with a content of 25.5%.
[0036] Example 3
[0037] In a 1 L reactor, 820 g of 98% sulfuric acid and 93 g of 98% nitric acid were added. Stirring was started, and NO gas was slowly introduced into the mixed acid. The reaction temperature was controlled at 50 - 70°C. When the solution turned blue, the gas introduction was stopped, and the temperature was lowered for discharging to obtain nitrosylsulfuric acid product with a content of 53.8%.
[0038] Example 4
[0039] In a 1 L reactor, 996 g of 85% sulfuric acid and 2 g of 98% nitric acid were added. Stirring was started, and NO gas was slowly introduced into the mixed acid. The reaction temperature was controlled at 60 - 70°C. When the solution turned blue, the gas introduction was stopped, and the temperature was lowered for discharging to obtain nitrosylsulfuric acid product with a content of 1.2%.
[0040] Example 5
[0041] In a 1 L reactor, 745 g of 90% sulfuric acid, 17.0 g of 98% nitric acid, and 200.0 g of nitrosylsulfuric acid were added. Stirring was started, and NO gas was slowly introduced into the mixed acid. The reaction temperature was controlled at 60 - 70°C. When the solution turned blue, the gas introduction was stopped, and the temperature was lowered for discharging to obtain nitrosylsulfuric acid with a content of 30.2%.
[0042] Example 6
[0043] Ammonia - air mixed gas with an ammonia volume fraction of 12% was introduced into an ammonia oxidation furnace and reacted at 850°C to generate NO gas (in addition to NO, it also contained N 2 , NO 2 , O 2 and a small amount of water vapor). After condensation and cooling to 20 - 50°C, the condensed water was separated, and then the gas was introduced into a reaction kettle filled with mixed acid (nitric acid 15 - 20%). When the solution turned blue, nitrosylsulfuric acid could be obtained.
[0044] In addition, nitric acid oxidation waste gas with a higher NO content, whose main components are similar to ammonia oxidation gas, can be used to prepare nitrosylsulfuric acid according to the above method.
[0045] Example 7
[0046] In a 1 L reactor, 920 g of 98% sulfuric acid and 67.5 g of 98% nitric acid were added. Stirring was started, and NO gas was slowly introduced into the mixed acid. The reaction temperature was controlled at 120 - 130°C. When approaching the end point, the temperature was lowered to 50 - 70°C for continuous reaction. When the solution turned blue, the gas introduction was stopped, and the temperature was lowered for discharging to obtain nitrosylsulfuric acid.
[0047] Example 8
[0048] In five 1L reactors, 870 g of 98% sulfuric acid and 67.5 g of 98% nitric acid were respectively added. Stirring was started. NO gas was introduced through the bottom inlet pipe at the inlet of the No. 1 reactor and discharged from the outlet, then entered the bottom inlet pipe of the No. 2 reactor. In this way, it passed through the five reactors in sequence, and finally the gas was discharged from the No. 5 reactor. The reaction temperature was controlled at 30 - 70 °C. When the solution in the No. 1 reactor turned blue, the gas supply could be closed, the temperature was lowered, and the material was discharged. Then, the material was reloaded, and the gas pipeline was switched so that it became the reactor at the end of the gas supply. Production was carried out in this cycle.
[0049] Example 9
[0050] In eight 1L reactors numbered 1 - 8, mixed acid was respectively added. Stirring was started. NO gas was passed through the mixed acid in the eight reactors in sequence. The reaction temperature was controlled at 50 - 70 °C. When the solutions in the first and second reactors turned blue, mixed acid was added to the No. 8 reactor. At the same time, the material in the No. 8 reactor flowed to the No. 7 reactor, the No. 7 reactor flowed to the No. 6 reactor, and so on to the No. 1 reactor. The material in the No. 1 reactor was slowly discharged and cooled to 40 °C and then sent to the storage tank. In this way, the flow directions of the mixed acid and the gas were opposite to form continuous feeding and discharging.
[0051] Example 10
[0052] Using a tower reactor, a packed tower or a plate tower, mixed acid was input from the top of the tower, and NO gas was introduced from the bottom of the tower. The gas supply rate was adjusted so that the nitric acid in the bottom liquid disappeared and the solution was blue. The product was cooled at the bottom of the tower and then transported to the storage tank.
[0053] Comparative Example
[0054] In a 1L reactor, 50 g of 40% nitrosylsulfuric acid, 870 g of 98% sulfuric acid, and 202.5 g of 98% nitric acid were added. Stirring was started. SO 2 gas was slowly introduced into the mixed acid. The pressure was controlled not to exceed 0.20 MPa, and the reaction temperature was 20 - 60 °C. When the solution turned blue, the gas supply was stopped, the temperature was lowered, and the material was discharged to obtain a nitrosylsulfuric acid product with a content of 39.5%.
[0055] The above are only the preferred embodiments of the present invention, and do not impose any formal or substantial limitations on the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the method of the present invention, several improvements and supplements can still be made, and these improvements and supplements should also be regarded as the protection scope of the present invention. For those skilled in the art, without departing from the spirit and scope of the present invention, any minor changes, modifications, and equivalent variations made using the above-disclosed technical content are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications, and variations made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solutions of the present invention.
Claims
1. A method for preparing nitrosyl sulfuric acid, characterized in that, The method includes reacting a mixed acid with a gas containing nitrogen monoxide to generate nitrosylsulfuric acid. The gas containing nitrogen monoxide is from a gas including ammonia oxidation products, nitric acid oxidation waste gas, or combustion waste gas. The equation for the reaction is: 2NO + HNO 3 + 3H 2 SO 4 =3NOHSO 4 + 2H 2 O.
2. The method for preparing nitrosyl sulfuric acid according to claim 1, characterized in that, The nitrogen monoxide-containing gas is a single nitrogen monoxide gas or a mixed gas of nitrogen monoxide and one or more of NO 2 , N 2 O 3 , SO 2 , SO 3 , O 2 , H 2 O, N 2 , CO 2 , CO.
3. The method for preparing nitrosyl sulfuric acid according to claim 1, characterized in that, In the nitric oxide-containing gas, the amount of substance of nitric oxide is M NO The sum with twice the amount of substance of sulfur dioxide, Mso 2 is greater than the amount of substance of nitrogen dioxide, M NO2 , that is, M NO + 2Mso 2 > M NO2 .
4. The method for preparing nitrosyl sulfuric acid according to claim 1 or 2 or 3, characterized in that, the ammonia oxidation product is prepared by reacting ammonia with air or oxygen.
5. The method for preparing nitrosyl sulfuric acid according to claim 4, characterized in that, the molar ratio of ammonia to oxygen is 1:1.2 - 1:2.
0.
6. The method for preparing nitrosyl sulfuric acid according to claim 1, characterized in that, when the gas containing nitric oxide reacts with the mixed acid, the gas pressure is 0.05 - 3.0 Mpa.
7. The method for preparing nitrosyl sulfuric acid according to claim 1, characterized in that, in the mixed acid, the mass percentage of sulfuric acid is 60 - 99%, the mass percentage of nitric acid is 0.1 - 11%, the mass percentage of water is 0 - 30%, and the mass percentage of nitrosyl sulfuric acid is 0 - 55%.
8. The method for preparing nitrosyl sulfuric acid according to claim 7, characterized in that, the sulfuric acid includes fuming sulfuric acid.
9. The method for preparing nitrosyl sulfuric acid according to claim 1, characterized in that, the reaction temperature is -10°C to 140°C, and the temperature at the end of the reaction is 20°C - 80°C.
10. The method for preparing nitrosyl sulfuric acid according to claim 1, characterized in that, the reaction includes batch reaction or continuous flow reaction.