Method and device for detecting pH value of methyl high-hydrogen-content silicone oil

Abstract

The invention provides a method and a device for detecting the pH value of methyl high-hydrogen-content silicone oil, according to the detection method, free hydrogen ions are extracted with water by using a liquid-liquid extraction method, the extraction process is more sufficient through heating boiling and stirring treatment, the density of the methyl high-hydrogen-content silicone oil is similar to that of water, and toluene is added to change the density of the methyl high-hydrogen-content silicone oil, so that the pH value of the methyl high-hydrogen-content silicone oil is increased. Meanwhile, the silicone oil and water are layered through centrifugal treatment, the effect of separating a hydrogen-containing water phase from methyl high-hydrogen-content silicone oil is achieved through filtering, pH detection is conducted on the hydrogen-containing water phase, errors caused by low hydrogen ion content in a traditional titration method are avoided, and the accuracy of a detection result is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of analytical detection, and particularly relates to a method and a device for detecting the acidity and alkalinity of methyl hydrogen polysiloxane. Background Art

[0002] Methyl hydrogen polysiloxane is an important class of organosilicon compounds, which are widely used in the fields of chemical industry, textile, medicine, etc. During its production and storage, due to the presence of free chloride ions, the chloride ions will combine with the free hydrogen ions in the sample to form Cl—H electron pairs, resulting in the product being acidic. This acidity may have an adverse impact on the use of downstream customers. Therefore, accurately determining the acidity and alkalinity of methyl hydrogen polysiloxane is crucial for product quality control.

[0003] Traditional methods for determining acidity and alkalinity (such as pH test paper method, pH meter method) mainly target the H⁺ concentration in aqueous solutions, while methyl hydrogen polysiloxane is a non-aqueous system and the source of acidity is special. At present, the industry standard uses a non-aqueous titration method to directly titrate the hydrogen ions in methyl hydrogen polysiloxane. However, due to the low content of free hydrogen ions in methyl hydrogen polysiloxane, a small error in endpoint judgment during the titration process may lead to a large relative error in the detection result, affecting the accurate determination of product quality.

[0004] In view of the above problems, the prior art has not provided a method that can efficiently, accurately, and simply determine the acidity and alkalinity of methyl hydrogen polysiloxane. Summary of the Invention

[0005] The present invention provides a method and a device for detecting the acidity and alkalinity of methyl hydrogen polysiloxane, which are used to solve the problems such as large detection errors in the prior art for detecting the acidity and alkalinity of methyl hydrogen polysiloxane.

[0006] In a first aspect, the present invention provides a method for detecting the acidity and alkalinity of methyl hydrogen polysiloxane, including the following steps: (1) Mix methyl hydrogen polysiloxane with water and toluene, perform boiling treatment to obtain a gas phase and a liquid phase, and condense the gas phase back into the liquid phase to re-participate in the boiling treatment; (2) After the liquid phase is cooled, it is filled into a sealed container and subjected to stirring extraction treatment to obtain a mixed solution; (3) Perform centrifugation treatment and filtration treatment on the mixed solution in sequence to obtain a hydrogen-containing aqueous phase and a toluene-containing silicone oil phase; (4) Perform pH detection treatment on the hydrogen-containing aqueous phase to obtain the acidity and alkalinity of methyl hydrogen polysiloxane.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: The liquid-liquid extraction method is used to extract free hydrogen ions with water, and the extraction process is made more sufficient by heating and boiling and stirring treatment. Since the density of methyl hydrogen polysiloxane is close to that of water, toluene is added to change its density, and at the same time, centrifugation is used to separate the silicone oil and water layers, and the hydrogen-containing aqueous phase and methyl hydrogen polysiloxane are separated by filtration. The pH of the hydrogen-containing aqueous phase is detected, avoiding the error caused by the low hydrogen ion content in the traditional titration method and improving the accuracy of the detection result.

[0008] Further, the volume ratio of methyl hydrogen polysiloxane, water and toluene is 2:2:1.

[0009] Further, the conductivity of water is less than 5.0 μS / cm, the pH value is 5-7, and it is treated by heating and boiling.

[0010] Further, the boiling treatment time is 30-45 min.

[0011] Further, the temperature of the stirring extraction treatment is 20-30 °C, the time is 30-45 min, and the rotation speed is 100-150 rpm.

[0012] Further, the temperature of the centrifugation treatment is 20-30 °C, the time is 3-5 min, and the rotation speed is 3000-5000 rpm.

[0013] Further, the filtration treatment is carried out using filter paper, and the filter paper is neutral quantitative filter paper.

[0014] Further, the pH detection treatment is carried out using a pH test paper or a pH meter.

[0015] Further, the content of hydrogen chloride in methyl hydrogen polysiloxane is not higher than 5 ppm.

[0016] In the second aspect, the present invention provides a device for detecting the acidity and alkalinity of methyl hydrogen polysiloxane, which is used to perform the method for detecting the acidity and alkalinity of methyl hydrogen polysiloxane described in the first aspect, including: a heating and condensation reflux unit, a sealed extraction unit, a centrifugation unit, a filtration unit and a pH detection unit; Among them, methyl hydrogen polysiloxane, water and toluene enter the heating and condensation reflux unit from the inlet of the heating and condensation reflux unit. The outlet of the heating and condensation reflux unit is communicated with the inlet of the sealed extraction unit. The outlet of the sealed extraction unit is communicated with the inlet of the centrifugation unit. The hydrogen-containing aqueous phase outlet of the centrifugation unit is communicated with the inlet of the filtration unit. The filtrate outlet of the filtration unit is communicated with the inlet of the pH detection unit. The pH detection unit is used to output the acidity and alkalinity result of methyl hydrogen polysiloxane. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the heating and condensation reflux unit in an embodiment of the present invention; Figure 2 Schematic diagram of the sealed extraction unit in an embodiment of the present invention; Figure 3 Schematic diagram of the filtration unit in an embodiment of the present invention.

[0018] Explanation of reference numerals: 1, condenser; 2, round-bottom flask; 4, electric heating mantle; 5, iodine flask; 7, magnetic stirrer; 8, funnel; 9, quantitative filter paper; 10, toluene-containing silicone oil phase; 11, beaker; 12, hydrogen-containing aqueous phase. Detailed implementation manners

[0019] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] In a first aspect, the present invention provides a method for detecting the pH value of methyl hydrogen polysiloxane, including the following steps: (1) Mix methyl hydrogen polysiloxane with water and toluene, perform boiling treatment to obtain a gas phase and a liquid phase, and condense the gas phase back into the liquid phase to re-participate in the boiling treatment; (2) After the liquid phase is cooled, it is filled into a sealed container and subjected to stirring extraction treatment to obtain a mixed solution; (3) Centrifuge and filter the mixed solution in sequence to obtain a hydrogen-containing aqueous phase and a toluene-containing silicone oil phase; (4) Perform pH detection on the hydrogen-containing aqueous phase to obtain the pH value of methyl hydrogen polysiloxane.

[0021] Specifically, since the density of methyl hydrogen polysiloxane is close to that of water, it is difficult to form layers and emulsify when directly extracted with water. Therefore, the boiling treatment in the present invention is to stimulate the adsorbed hydrogen ions in methyl hydrogen polysiloxane to make the hydrogen ions become free state, which is better extracted by water; during the boiling process, the gas phase is condensed back into the liquid phase to ensure that volatile components are not lost and improve the extraction efficiency; then through stirring extraction treatment, by using the polarity of water and the density adjustment function of toluene, the free hydrogen ions in the sample are fully extracted. Through centrifugation and filtration, efficient separation of the hydrogen-containing aqueous phase and the toluene-containing silicone oil phase is achieved. Then, using a pH detection that is more sensitive to the hydrogen ion content to replace the titration hydrogen ion detection result improves the accuracy of the pH value detection method and avoids the influence caused by titration errors.

[0022] The method for detecting the acidity and alkalinity of methyl hydrogen polysiloxane provided by the present invention uses the liquid-liquid extraction method to extract free hydrogen ions with water, and makes the extraction process more sufficient through heating and boiling and stirring treatment. Since the density of methyl hydrogen polysiloxane is similar to that of water, toluene is added to change its density, and at the same time, centrifugation is used to separate the silicone oil and water, and filtration is carried out to achieve the separation effect of hydrogen-containing aqueous phase and methyl hydrogen polysiloxane. The pH of the hydrogen-containing aqueous phase is detected, avoiding the error caused by the low content of hydrogen ions in the traditional titration method and improving the accuracy of the detection result.

[0023] Further, the volume ratio of methyl hydrogen polysiloxane, water and toluene is 2:2:1.

[0024] By controlling the mass ratio of methyl hydrogen polysiloxane, water and toluene, the extraction efficiency and separation effect are ensured to reach the best balance, and the accuracy of the detection method is further improved.

[0025] Among them, the conductivity of water is less than 5.0 μS / cm, the pH value is 5-7, and it is treated by heating and boiling. The water uses distilled water above grade three in the laboratory, and the carbon dioxide in it is removed by boiling. It cannot be stored and is prepared immediately before use.

[0026] Further ensure that the concentration of hydrogen ions in the extract accurately reflects the actual acidity in the sample and improve the reliability of the detection result.

[0027] In a specific embodiment, the boiling treatment time is 30-45 min, the temperature of the stirring extraction treatment is 20-30 °C, the time is 30-45 min, and the rotation speed is 100-150 rpm; the temperature of the centrifugation treatment is 20-30 °C, the time is 3-5 min, and the rotation speed is 3000-5000 rpm.

[0028] By limiting the specific execution parameters, the free hydrogen ions can be further fully transferred to the aqueous phase, improving the extraction efficiency and the accuracy of the detection method.

[0029] In a specific embodiment, the filtration treatment is carried out using filter paper, and the filter paper is neutral quantitative filter paper. Since methyl hydrogen polysiloxane has strong hydrophobicity, when using filter paper to filter the solution, water can pass through the filter paper while silicone oil cannot pass through without external force, thus achieving the separation effect of water and methyl hydrogen polysiloxane.

[0030] Specifically, the pH detection treatment is carried out using pH test paper or a pH meter.

[0031] Further, the content of hydrogen chloride in methyl hydrogen polysiloxane is not higher than 5 ppm.

[0032] In a second aspect, the present invention provides a device for detecting the acidity and alkalinity of methyl hydrogen polysiloxane, which is used to execute the method for detecting the acidity and alkalinity of methyl hydrogen polysiloxane described in the first aspect, and includes: a heating and condensation reflux unit, a sealed extraction unit, a centrifugation unit, a filtration unit, and a pH detection unit; Among them, methyl hydrogen polysiloxane, water, and toluene enter the heating and condensation reflux unit from the inlet of the heating and condensation reflux unit. The outlet of the heating and condensation reflux unit is communicated with the inlet of the sealed extraction unit. The outlet of the sealed extraction unit is communicated with the inlet of the centrifugation unit. The hydrogen-containing aqueous phase outlet of the centrifugation unit is communicated with the inlet of the filtration unit. The filtrate outlet of the filtration unit is communicated with the inlet of the pH detection unit. The pH detection unit is used to output the acidity and alkalinity result of methyl hydrogen polysiloxane.

[0033] Please refer to Figures 1-3 , in a specific embodiment, the heating and condensation reflux unit includes a round-bottom flask 2 and an upper-connected condenser 1, and an electric heating mantle 4 is used to heat the round-bottom flask 2; the sealed extraction unit includes an iodine flask 5, the iodine flask 5 is placed on a magnetic stirrer 7, the centrifugation unit includes a centrifuge, the filtration unit includes a funnel 8 and a quantitative filter paper 9, and the pH detection unit includes a beaker 11 and a pH meter.

[0034] Hereinafter, the method for detecting the acidity and alkalinity of methyl hydrogen polysiloxane provided by the present invention will be introduced in detail through specific embodiments. Example 1

[0035] Mix 100 mL of methyl hydrogen polysiloxane, 100 mL of water, and 50 mL of toluene, add them to the round-bottom flask 2, add a boiling chip, heat the round-bottom flask 2 with an electric heating mantle 4, and perform boiling treatment for 30 min. A condenser 1 is connected above the round-bottom flask 2. The gas phase obtained by boiling is condensed by the condenser 1 and then flows back into the round-bottom flask 2 to participate in the boiling treatment again; After the liquid phase is cooled, pour it into the iodine flask 5 and cover it with a glass stopper; place the iodine flask 5 on a magnetic stirrer 7 for stirring extraction treatment for 30 min, and then remove the iodine flask 5 to obtain a mixed solution; Pour the mixed solution evenly into centrifuge tubes, symmetrically place them in a centrifuge, and perform centrifugation treatment for 3 min to separate water and oil; filter the centrifuged solution through filter paper to obtain a hydrogen-containing aqueous phase 12 and a toluene-containing silicone oil phase 10; The hydrogen-containing aqueous phase 12 passes through the filter paper, while the toluene-containing silicone oil phase 10 is intercepted on the filter paper due to its hydrophobicity, thus achieving a separation effect; After the extract is fixed to 100 mL, use a pH meter to detect its pH value, and at the same time perform a blank test.

[0036] The measurement results show that the pH value of the extract is 6.

[0037] The pH meter detects the pH value of the extraction solution. Since the volume of the silicone oil sample is equal to that of water and the H+ concentration remains unchanged, the detected result is the pH value of the silicone oil. If the value is lower than 7, it indicates that the silicone oil is acidic, and the lower the value, the stronger the acidity.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; if these modifications and variations fall within the scope of the claims of the present invention and its equivalent technologies, they should all be considered as the protection scope of the present invention.

Claims

1. A method for detecting the acidity and alkalinity of methyl hydrogen polysiloxane, characterized in that, It includes the following steps: (1) Mix methyl hydrogen polysiloxane with water and toluene, carry out boiling treatment to obtain a gas phase and a liquid phase, and condense the gas phase back into the liquid phase to re-participate in the boiling treatment; (2) After the liquid phase is cooled, it is filled into a sealed container and subjected to stirring extraction treatment to obtain a mixed liquid; (3) The mixed liquid is successively subjected to centrifugation treatment and filtration treatment to obtain a hydrogen-containing aqueous phase and a toluene-containing silicone oil phase; (4) The hydrogen-containing aqueous phase is subjected to pH detection treatment to obtain the acidity and alkalinity of methyl hydrogen polysiloxane.

2. The method for detecting the pH value of methyl hydrogen polysiloxane according to claim 1, wherein The volume ratio of methyl hydrogen polysiloxane, water and toluene is 2:2:

1.

3. The method for detecting the pH value of methyl hydrogen polysiloxane according to claim 1, characterized in that The conductivity of water is less than 5.0 μS / cm, the pH value is 5-7, and it is subjected to heating and boiling treatment.

4. The method for detecting the pH value of methyl hydrogen polysiloxane according to claim 1, wherein, The time of boiling treatment is 30-45 min.

5. The method for detecting the pH value of methyl hydrogen polysiloxane according to claim 1, characterized in that, The temperature of the stirring extraction treatment is 20-30 °C, the time is 30-45 min, and the rotation speed is 100-150 rpm.

6. The method for detecting the pH value of methyl hydrogen polysiloxane according to claim 1, wherein The temperature of the centrifugation treatment is 20-30 °C, the time is 3-5 min, and the rotation speed is 3000-5000 rpm.

7. The method for detecting the pH value of methyl hydrogen polysiloxane according to claim 1, wherein The filtration treatment is carried out using filter paper, and the filter paper is a neutral quantitative filter paper.

8. The method for detecting the pH value of methyl hydrogen polysiloxane according to claim 1, characterized in that, The pH detection treatment is carried out using pH test paper or a pH meter.

9. The method for detecting the pH value of methyl hydrogen polysiloxane according to claims 1-8, characterized in that, The content of hydrogen chloride in methyl hydrogen polysiloxane is not higher than 5 ppm.

10. A device for detecting the acidity and alkalinity of methyl hydrogen polysiloxane, which is used to perform the method for detecting the acidity and alkalinity of methyl hydrogen polysiloxane according to any one of claims 1-9, characterized in that, It includes: A heating and condensation reflux unit, a sealed extraction unit, a centrifugation unit, a filtration unit and a pH detection unit; Among them, methyl hydrogen polysiloxane, water and toluene enter the heating and condensation reflux unit from the inlet of the heating and condensation reflux unit. The outlet of the heating and condensation reflux unit is connected to the inlet of the sealed extraction unit. The outlet of the sealed extraction unit is connected to the inlet of the centrifugation unit. The hydrogen-containing aqueous phase outlet of the centrifugation unit is connected to the inlet of the filtration unit. The filtrate outlet of the filtration unit is connected to the inlet of the pH detection unit. The pH detection unit is used to output the acidity and alkalinity result of methyl hydrogen polysiloxane.

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