Method for improving the potassium permanganate oxidation time of ethanol
Patent Information
- Application Number
- CN202610986393.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-03
- Publication Date
- 2026-09-25
AI Technical Summary
本发明直接针对影响高锰酸钾氧化时间的还原性物质，通过精准的预氧化反应将其有效去除，能够将氧化时间从10分钟大幅提升至15分钟以上，甚至达到26分钟或更高，满足了优级乙醇的标准，且操作简便、成本低廉、效果显著，满足乙醇更高品级的标准要求。
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Figure CN122809984A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of ethanol refining technology, specifically a method for increasing the oxidation time of ethanol with potassium permanganate. Background Technology
[0002] Ethanol, as an important basic chemical and clean fuel, requires strict control over its purity through a number of physicochemical indicators. Among them, "potassium permanganate oxidation time" is a core indicator, which directly reflects the total content of easily oxidized reducing impurities in ethanol (such as aldehydes, unsaturated compounds, and lower alcohols).
[0003] With the development of modern coal chemical technologies such as syngas catalytic ethanol production, the output of coal-based ethanol is increasing daily. However, the products of this process often inevitably contain trace amounts of reducing byproducts such as aldehydes and ketones. The presence of these impurities will cause a rapid reaction with potassium permanganate in the standard test, consuming the potassium permanganate and thus significantly shortening the oxidation time. In practice, many qualified coal-based ethanol products perform poorly in this key indicator; for example, the oxidation time is only around 10 minutes or even lower, far below the superior grade standard, severely restricting product quality improvement and market value.
[0004] Currently, the industry commonly employs precision distillation or adsorbents (such as activated carbon and molecular sieves) to improve ethanol purity. However, these methods have significant limitations: precision distillation is extremely energy-intensive, places stringent demands on equipment, and has limited effectiveness in separating impurities with boiling points close to ethanol; while adsorption methods are somewhat effective, they suffer from limited adsorption capacity, frequent regeneration or replacement of adsorbents, high operating costs, and unclear selectivity for different impurities. Therefore, developing a post-treatment technology that can efficiently, economically, and specifically address the short oxidation time of potassium permanganate in coal-based ethanol has become a pressing practical problem in this field. Summary of the Invention
[0005] The purpose of this invention is to provide a method for increasing the oxidation time of ethanol with potassium permanganate, a method that is simple to operate, low in cost, and has significant effects in increasing the oxidation time of ethanol with potassium permanganate. This method can effectively remove reducing substances from ethanol, thereby significantly increasing the oxidation time of ethanol with potassium permanganate from a low level to more than 15 minutes, meeting the standard requirements of higher grades, and solving the problems mentioned in the background art.
[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for increasing the oxidation time of ethanol with potassium permanganate includes: S1. Pre-oxidation treatment: Add potassium permanganate solution to the ethanol sample to be treated. The concentration of potassium permanganate is calculated in basic units, c(1 / 5KMnO4) is 0.001 ~ 0.02 mol / L, the upper limit of potassium permanganate is controlled within 0.000025 mol, and the product of the volume of potassium permanganate solution added and the concentration of potassium permanganate solution is less than 0.000025 mol. Mix and shake to carry out the oxidation reaction, so that the reducing substances in ethanol react with potassium permanganate. S2. Precipitation: Cool the mixture after the reaction in step S1 to promote the precipitation and aggregation of manganese dioxide precipitate; S3. Solid-liquid separation: The mixture after cooling in step S2 is filtered to remove the generated manganese dioxide precipitate and the pre-oxidized ethanol filtrate is collected.
[0007] As a further aspect of the present invention: the ethanol sample to be processed is coal-based ethanol or bioethanol.
[0008] As a further embodiment of the present invention: In step S1, the potassium permanganate solution is prepared by diluting a standard potassium permanganate solution. The solvent used for dilution is deionized water, and its concentration, calculated in basic units of potassium permanganate, is c(1 / 5KMnO4) of 0.001 ~ 0.02 mol / L.
[0009] As a further aspect of the present invention: in step S1, c(1 / 5KMnO4) is 0.005 mol / L.
[0010] As a further aspect of the present invention: in step S1, the sampling volume of the ethanol sample to be processed is 55ml~65ml, and it is placed in a stoppered test tube. The volume ratio of the potassium permanganate solution added to the volume of the ethanol sample is (0.5:50)~(5:50), and the shaking time is 3~15 minutes.
[0011] As a further embodiment of the present invention: the volume ratio of the potassium permanganate solution added to the ethanol sample is 1:50, and the shaking time is 5 minutes.
[0012] As a further aspect of the present invention, the cooling step in step S2 is as follows: the container containing the mixture is placed in an environment of 0°C to 10°C for 5 to 15 minutes to cool down.
[0013] As a further aspect of the present invention: in step S2, the container containing the mixture is placed at 5°C and cooled for 10 minutes.
[0014] As a further aspect of the present invention: in step S3, the filtration is performed using a filter membrane or filter paper with a pore size of 0.1~25µm.
[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention directly targets the reducing substances that affect the oxidation time of potassium permanganate, and effectively removes them through a precise pre-oxidation reaction. It can significantly increase the oxidation time from 10 minutes to more than 15 minutes, or even 26 minutes or higher, meeting the standards for superior grade ethanol. Moreover, it is easy to operate, low in cost, and has significant effects, meeting the standard requirements for higher grades of ethanol. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of a method for increasing the oxidation time of ethanol with potassium permanganate. Figure 2 A comparison of the results of potassium permanganate oxidation time of pre-oxidized and un-pre-oxidized ethanol after 1 hour; Figure 3 The color change diagram after adding excess potassium permanganate; Figure 4 This is a precipitation diagram of potassium permanganate solution; Detailed Implementation
[0018] Please see Figures 1-4 : Example 1
[0019] Step S1 Pre-oxidation treatment: Take 50 ml of coal-based ethanol sample and place it in a stoppered test tube. Accurately add 0.3 ml of potassium permanganate aqueous solution with a concentration of c(1 / 5KMnO4) = 0.005 mol / L using a pipette. This solution is prepared by diluting potassium permanganate standard solution 20 times with deionized water as the diluent. After mixing, shake for 5 minutes to allow the reducing substances in the ethanol to react fully with the potassium permanganate.
[0020] Precipitation in step S2: The reacted mixture was cooled in 5°C water for 10 minutes to promote the precipitation and aggregation of manganese dioxide.
[0021] Step S3: Solid-liquid separation The cooled mixture was filtered using medium-speed filter paper with a pore size of 0.45µm to remove manganese dioxide precipitate, and the filtrate was collected.
[0022] Step S4 detection: The potassium permanganate oxidation time of the filtrate was tested according to the standard method of GB / T 394.2-2008, and the result was 15 minutes, which was significantly improved compared with 10 minutes before treatment.
[0023] Comparative Example 1-1 Step S1 Pre-oxidation treatment: Take 50 ml of coal-based ethanol sample and place it in a stoppered test tube. Accurately add 0.3 ml of potassium permanganate aqueous solution with a concentration of c(1 / 5KMnO4) = 0.001 mol / L using a pipette. This solution is prepared by diluting potassium permanganate standard solution 20 times with deionized water as the diluent. After mixing, shake for 5 minutes to allow the reducing substances in the ethanol to react fully with the potassium permanganate.
[0024] Precipitation in step S2: The reacted mixture was cooled in 5°C water for 10 minutes to promote the precipitation and aggregation of manganese dioxide.
[0025] Step S3: Solid-liquid separation The cooled mixture was filtered using medium-speed filter paper with a pore size of 0.45µm to remove manganese dioxide precipitate, and the filtrate was collected.
[0026] Step S4 detection: The potassium permanganate oxidation time of the filtrate was tested according to the standard method of GB / T 394.2-2008, and the result was 12 minutes.
[0027] Comparative Examples 1-2 Step S1 Pre-oxidation treatment: Take 50 ml of coal-based ethanol sample and place it in a stoppered test tube. Accurately add 0.3 ml of a potassium permanganate aqueous solution with a concentration of c(1 / 5KMnO4) = 0.02 mol / L using a pipette. This solution is prepared by diluting a potassium permanganate standard solution 20 times with deionized water as the diluent. After mixing, shake for 5 minutes to allow the reducing substances in the ethanol to react fully with the potassium permanganate.
[0028] Precipitation in step S2: The reacted mixture was cooled in 5°C water for 10 minutes to promote the precipitation and aggregation of manganese dioxide.
[0029] Step S3: Solid-liquid separation The cooled mixture was filtered using medium-speed filter paper with a pore size of 0.45µm to remove manganese dioxide precipitate, and the filtrate was collected.
[0030] Step S4 detection: The potassium permanganate oxidation time of the filtrate was tested according to the standard method of GB / T 394.2-2008, and the result was 24 minutes.
[0031] In summary, when 0.3 ml of potassium permanganate aqueous solution with a concentration of c(1 / 5KMnO4) = 0.001 mol / L was added, the oxidation time began to increase, and when the concentration was increased to 0.02 mol / L, the result was 24 minutes.
[0032] Comparative Examples 1-3 Take 50 ml of coal-based ethanol sample and place it in a stoppered test tube. Accurately add 0.3 ml of potassium permanganate aqueous solution with a concentration of c(1 / 5KMnO4) = 0.005 mol / L (prepared by diluting potassium permanganate standard solution 20 times with deionized water as the diluent) using a pipette. After mixing, shake for 5 minutes to allow the reducing substances in the ethanol to react fully with the potassium permanganate. Let the mixture stand at room temperature for 10 minutes; no precipitation occurred. As shown in Comparative Examples 1-3, precipitation does not occur at room temperature; therefore, cooling is necessary.
[0033] Example 2
[0034] The method in this embodiment is as follows: Step S1 Pre-oxidation treatment: Take 50 ml of coal-based ethanol sample and place it in a stoppered test tube. Accurately add 0.6 ml of a potassium permanganate aqueous solution with a concentration of c(1 / 5KMnO4) = 0.005 mol / L (prepared by diluting a standard potassium permanganate solution with c(1 / 5KMnO4) = 0.1 mol / L 20 times, using deionized water as the diluent) using a pipette. After mixing, shake for 5 minutes to allow the reducing substances in the ethanol to react fully with the potassium permanganate.
[0035] Precipitation in step S2: The reacted mixture was cooled in 5°C water for 10 minutes to promote the precipitation and aggregation of manganese dioxide.
[0036] Step S3: Solid-liquid separation The cooled mixture was filtered using medium-speed filter paper with a pore size of 0.45µm to remove manganese dioxide precipitate, and the filtrate was collected.
[0037] Step S4 detection: The potassium permanganate oxidation time of the filtrate was tested according to the standard method of GB / T 394.2-2008, and the result was 20 minutes, which was significantly improved compared with 10 minutes before treatment.
[0038] Example 3
[0039] The method in this embodiment is as follows: Step S1 Pre-oxidation treatment: Take 50 ml of coal-based ethanol sample and place it in a stoppered test tube. Accurately add 1 ml of potassium permanganate aqueous solution with a concentration of c(1 / 5KMnO4) = 0.005 mol / L (prepared by diluting a standard potassium permanganate solution with c(1 / 5KMnO4) = 0.1 mol / L 20 times, using deionized water as the diluent) using a pipette. After mixing, shake for 5 minutes to allow the reducing substances in the ethanol to react fully with the potassium permanganate.
[0040] Precipitation in step S2: The reacted mixture was cooled in 5°C water for 10 minutes to promote the precipitation and aggregation of manganese dioxide.
[0041] Step S3: Solid-liquid separation The cooled mixture was filtered using medium-speed filter paper with a pore size of 0.45µm to remove manganese dioxide precipitate, and the filtrate was collected.
[0042] Step S4 detection: The potassium permanganate oxidation time of the filtrate was tested according to the standard method of GB / T 394.2-2008, and the result was 26 minutes, which was significantly improved compared with 10 minutes before treatment.
[0043] Example 4
[0044] The method in this embodiment is as follows: Step S1 Pre-oxidation treatment: Take 50 ml of coal-based ethanol sample and place it in a stoppered test tube. Accurately add 1.5 ml of potassium permanganate aqueous solution with a concentration of c(1 / 5KMnO4) = 0.005 mol / L (prepared by diluting a standard potassium permanganate solution with c(1 / 5KMnO4) = 0.1 mol / L 20 times, using deionized water as the diluent) using a pipette. After mixing, shake for 5 minutes to allow the reducing substances in the ethanol to react fully with the potassium permanganate.
[0045] Precipitation in step S2: The reacted mixture was cooled in 5°C water for 10 minutes to promote the precipitation and aggregation of manganese dioxide.
[0046] Step S3: Solid-liquid separation The cooled mixture was filtered using medium-speed filter paper with a pore size of 0.45µm to remove manganese dioxide precipitate, and the filtrate was collected.
[0047] Step S4 detection: The potassium permanganate oxidation time of the filtrate was tested according to the standard method of GB / T 394.2-2008, and the result was 26 minutes, which was significantly improved compared with 10 minutes before treatment.
[0048] Example 5
[0049] The method in this embodiment is as follows: Step S1 Pre-oxidation treatment: Take 50 ml of coal-based ethanol sample and place it in a stoppered test tube. Accurately add 5 ml of potassium permanganate aqueous solution with a concentration of c(1 / 5KMnO4) = 0.005 mol / L (prepared by diluting a standard potassium permanganate solution with c(1 / 5KMnO4) = 0.1 mol / L 20 times, using deionized water as the diluent) using a pipette. After mixing, shake for 5 minutes to allow the reducing substances in the ethanol to react fully with the potassium permanganate, but the color will turn abnormally yellow.
[0050] Precipitation in step S2: The reacted mixture was cooled in 5°C water for 10 minutes to promote the precipitation and aggregation of manganese dioxide.
[0051] Step S3: Solid-liquid separation The cooled mixture was filtered using medium-speed filter paper with a pore size of 0.45µm to remove manganese dioxide precipitate, and the filtrate was collected.
[0052] Step S4 detection: The potassium permanganate oxidation time of the filtrate was tested according to the standard method of GB / T 394.2-2008, and the result showed an abnormally yellow color, making comparison impossible.
[0053] Comparative Example 5-1 The method for this comparison is as follows: Step S1 Pre-oxidation treatment: Take 50 ml of coal-based ethanol sample and place it in a stoppered test tube. Accurately add 5 ml of potassium permanganate aqueous solution with a concentration of c(1 / 5KMnO4) = 0.001 mol / L using a pipette. Mix and shake for 5 minutes to allow the reducing substances in the ethanol to react fully with the potassium permanganate.
[0054] Precipitation in step S2: The reacted mixture was cooled in 5°C water for 10 minutes to promote the precipitation and aggregation of manganese dioxide.
[0055] Step S3: Solid-liquid separation The cooled mixture was filtered using medium-speed filter paper with a pore size of 0.45µm to remove manganese dioxide precipitate, and the filtrate was collected.
[0056] Step S4 detection: The potassium permanganate oxidation time of the filtrate was tested according to the standard method of GB / T 394.2-2008, and the result was 26 minutes, which was significantly improved compared with 10 minutes before treatment.
[0057] If: Take 50ml of coal-based ethanol sample, without any pretreatment, and directly test the potassium permanganate oxidation time according to the standard method of GB / T 394.2-2008, the result is 10 minutes.
[0058] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A method for increasing the oxidation time of ethanol with potassium permanganate, characterized in that: include: S1. Pre-oxidation treatment: Add potassium permanganate solution to the ethanol sample to be treated. The concentration of potassium permanganate is calculated in basic units, c(1 / 5KMnO4) is 0.001 ~ 0.02 mol / L, the upper limit of potassium permanganate is controlled within 0.000025 mol, and the product of the volume of potassium permanganate solution added and the concentration of potassium permanganate solution is less than 0.000025 mol. Mix and shake to carry out the oxidation reaction, so that the reducing substances in ethanol react with potassium permanganate. S2. Precipitation: Cool the mixture after the reaction in step S1 to promote the precipitation and aggregation of manganese dioxide precipitate; S3. Solid-liquid separation: The mixture after cooling in step S2 is filtered to remove the generated manganese dioxide precipitate and the pre-oxidized ethanol filtrate is collected.
2. The method for increasing the oxidation time of ethanol with potassium permanganate according to claim 1, characterized in that: The ethanol sample to be processed is either coal-based ethanol or bioethanol.
3. The method for increasing the oxidation time of ethanol with potassium permanganate according to claim 1, characterized in that: In step S1, the potassium permanganate solution is prepared by diluting a standard potassium permanganate solution, and the solvent used for dilution is deionized water.
4. The method for increasing the oxidation time of ethanol with potassium permanganate according to claim 3, characterized in that: In step S1, c(1 / 5KMnO4) is 0.005 mol / L.
5. The method for increasing the oxidation time of ethanol with potassium permanganate according to claim 1, characterized in that: In step S1, the sampling volume of the ethanol sample to be processed is greater than 50 ml, the volume ratio of the potassium permanganate solution added to the volume of the ethanol sample is (0.5:50) ~ (5:50), and the shaking time is 3 to 15 minutes.
6. The method for increasing the oxidation time of ethanol with potassium permanganate according to claim 1, characterized in that: The volume ratio of the potassium permanganate solution added to the ethanol sample is 1:50, and the shaking time is 5 minutes.
7. The method for increasing the oxidation time of ethanol with potassium permanganate according to claim 1, characterized in that: The cooling step in step S2 is as follows: place the container containing the mixture in an environment of 0℃~10℃ for 5~15 minutes to cool it down.
8. The method for increasing the oxidation time of ethanol with potassium permanganate according to claim 7, characterized in that: In step S2, the container containing the mixture is placed at 5°C and cooled for 10 minutes.
9. The method for increasing the oxidation time of ethanol with potassium permanganate according to claim 1, characterized in that: In step S3, the filtration is performed using a filter membrane or filter paper with a pore size of 0.1~25µm.