Preparation method of nickel element quality control sample in lubricating oil

Abstract

The invention discloses a preparation method of a nickel element quality control sample in lubricating oil, which comprises the following steps: step 1, adding an antioxidant into hydrocarbon oil base oil, heating at 50 DEG C for dissolving, and preparing a uniform solution; 2, taking two surfactants DO-46 and M-4, uniformly mixing, adding a water-phase nickel element metal standard solution, adding the solution prepared in the step 1, and fixing the volume to a target weight to obtain a prepared quality control sample; and 3, uniformly stirring the prepared quality control sample, and subpackaging and storing. The method has obvious advantages by adopting the water-phase metal standard solution as the solute. Compared with an organic metal compound as a solute, the water-phase metal standard solution is easier to obtain and has more types.

Description

Technical Field

[0001] The invention relates to the technical field of lubricating oil quality control sample or standard solution preparation, and in particular to a method for preparing a nickel element quality control sample in lubricating oil. Background Art

[0002] During the development process, organometallic compounds are used as additives, hydrocarbon base oil is used as a carrier, and appropriate co-solvents and antioxidants are added. After mixing, dissolving, and stirring, single / multi-element standard oils are obtained. However, it is difficult to find organometallic compounds suitable for some elements, such as nickel. Therefore, it is necessary to develop quality control samples for nickel elements. Summary of the invention

[0003] In order to solve the defects of the prior art, the present invention provides a method for preparing a quality control sample of nickel element in lubricating oil.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: The present invention discloses a method for preparing a quality control sample of nickel in lubricating oil, comprising the following steps: Step 1: adding an antioxidant to a hydrocarbon base oil, heating to 50° C. to dissolve the mixture, and preparing a uniform solution; Step 2: Take two surfactants, DO-46 and M-4, mix them evenly, add the aqueous nickel metal standard solution, and then add the solution prepared in step 1 to make the volume to the target weight to obtain a prepared quality control sample; Step 3: Stir the prepared quality control sample evenly and store it in aliquots.

[0005] As a preferred technical solution of the present invention, the antioxidant is T501 antioxidant.

[0006] As a preferred technical solution of the present invention, both DO-46 and M-4 surfactants are used at a concentration of 3%. M-4: Fatty alcohol and ethylene oxide condensation product, a type of fatty alcohol polyoxyethylene ether, is a fatty alcohol and ethylene oxide condensation product. It is a non-ionic surfactant and can be used as an emulsifier for making W / O emulsions. DO-46: Fatty alcohol polyoxyethylene ether (AEO), is an ether formed by the condensation of polyethylene glycol (PEG) and fatty alcohol. It is a non-ionic surfactant and can be used as an emulsifier for making W / O emulsions. As a preferred technical solution of the present invention, after step one, the process further includes determining the nickel content of the solution prepared in step one and the surfactants DO-46 and M-4 to be used.

[0007] As a preferred technical solution of the present invention, step three also includes conducting a uniformity test and a stability test on the prepared quality control sample.

[0008] As a preferred technical solution of the present invention, the uniformity test is carried out by inductively coupled plasma emission spectroscopy.

[0009] As a preferred technical solution of the present invention, the nickel content of the quality control sample is 100 mg / kg.

[0010] The beneficial effects of the present invention are: The present invention has obvious advantages by using aqueous metal standard solution as solute. Compared with organic metal compounds as solute, aqueous metal standard solution is easier to obtain and has more types. At the same time, organic metal compounds as solutes need to be tested for purity and value traceability, and aqueous metal standard solution is a certified standard substance and does not have the problem of value traceability. In the preparation process, surfactants are used to achieve mutual dissolution of oil and water, the preparation process is relatively simple, and the sample is clear and uniform after preparation. Through uniformity and stability tests, the quality control sample data results prepared by this method are uniform and stable, and the consistency is good with the standard solution results prepared by organic metal compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 It is a schematic diagram of the process of the present invention.

[0012] Figure 2 It is the uniformity test condition.

[0013] Figure 3 The uniformity test results.

[0014] Figure 4 The stability test results. DETAILED DESCRIPTION

[0015] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0016] Example 1: Figure 1 As shown, the following steps are included: 1. Accurately weigh 4.5g T501 antioxidant and add it to 1200g hydrocarbon base oil. Heat and stir at 50℃ until the antioxidant is completely dissolved in the base oil. Continue to add base oil, adjust the volume to 1500g, stir evenly and cool for use. Hydrocarbon base oil is the basic product and basic raw material of petrochemical industry, mainly composed of hydrocarbons such as alkanes and cycloalkanes. T501 antioxidant is a general phenolic antioxidant. As an oil-soluble antioxidant widely used at home and abroad, it has strong antioxidant ability, good heat resistance and stability, and can significantly improve the stability of oil products.

[0017] 2. Inductively coupled plasma emission spectrometry was used to test the antioxidant hydrocarbon oil base oil and two surfactants to check the nickel content. The nickel content was less than 1 mg / kg. Normally, the surfactant and base oil do not contain nickel. This step is to check the accuracy. If nickel is contained, the amount of nickel added in the subsequent steps is controlled to ensure that the nickel content of the final product is theoretically 100 mg / kg.

[0018] 3. Accurately weigh 45g of DO-46 and 45g of M-4 surfactant in the same container, and slowly stir to mix the two evenly and present a uniform state. Both surfactants are used at a concentration of 3%.

[0019] 4. Add 15g of 10000mg / L aqueous nickel standard solution to the mixed surfactant, mix well, add hydrocarbon base oil containing antioxidant, and adjust the volume to 1500g. Get the finished quality control sample. Surfactant, also known as surfactant, is a compound that can significantly reduce the surface tension or interfacial tension between two liquids. The molecular structure of surfactant has two properties: one end is a hydrophilic group and the other end is a hydrophobic group. The hydrophilic group is often a polar group, such as carboxylic acid, sulfonic acid, sulfuric acid, amino or amine group and its salt; the hydrophobic group is often a non-polar hydrocarbon chain, such as a hydrocarbon chain with more than 8 carbon atoms. This unique structure of the surfactant is usually called "amphiphilic structure". The DO-46 surfactant selected in this embodiment is an ether formed by the condensation of polyethylene glycol (PEG) and fatty alcohol. It is the fastest growing and most used variety among non-ionic surfactants; the selected M-4 surfactant is a condensate of fatty alcohol and ethylene oxide, which belongs to non-ionic surfactants and is a common lipophilic emulsifier.

[0020] The mixed quality control sample was stirred evenly, divided into 30 bottles, and stored at room temperature away from light. The 30 bottles were used for subsequent homogeneity and stability tests.

[0021] Ten bottles of quality control samples were randomly selected from 30 bottles and each bottle was independently measured twice using inductively coupled plasma emission spectrometry (conditions see Figure 2 ) for uniformity test. The uniformity test results were statistically analyzed using F test one-way analysis of variance. The results are shown in Figure 3 .

[0022] Store 2 bottles of samples in a 30℃ constant temperature box and a 0℃ refrigerator for 7 days and 15 days respectively. Take them out after the expiration date, and take samples to determine the nickel content after the quality control samples return to room temperature. Each bottle of sample is determined 3 times. The stability test results are statistically analyzed using the t-test method. The statistical results show that the stability of the quality control samples is good and meets the requirements. The results are shown in the table. Figure 4 .

[0023] Embodiment 2:

[0024] The difference between this embodiment and embodiment 1 is that this embodiment uses sodium sulfonate as a surfactant, and sodium sulfonate with a concentration of 9%, 10% and 15% is used separately for preparation. Among them, the 9% concentration and the 15% concentration are tested, and the lack of uniformity affects the solubility. After complete stirring and dissolution, the nickel element concentration of the product modulated by 9% sodium sulfonate is only 83mg / kg; the nickel element concentration of the product modulated by 15% sodium sulfonate is 91mg / kg. The stability of the products modulated by 10% and 15% sodium sulfonate is insufficient. Among them, the product modulated by 10% sodium sulfonate has an initial nickel element concentration of 94mg / kg, 96mg / kg after one week, 94mg / kg after two weeks, and 92mg / kg after three weeks. The product modulated by 15% sodium sulfonate has an initial concentration of 91mg / kg, 93mg / kg after one week, 91mg / kg after two weeks, and 90mg / kg after three weeks. The above data are all average values ​​of multiple measurements. In addition, the product prepared with sodium sulfonate as the surfactant has poor clarity, which may also be a defect caused by uniformity.

[0025] Embodiment 3:

[0026] The difference between this embodiment and embodiment 1 is that only DO46 is used as a surfactant. This embodiment uses 6%, 4%, and 3% concentrations of DO46 to modulate products. The uniformity does not meet the requirements. The average nickel concentration of the product corresponding to the 4% concentration is 120 mg / kg, the average nickel concentration of the product corresponding to the 6% concentration is 97 mg / kg, and the average nickel concentration of the product corresponding to the 3% concentration is 96 mg / kg.

[0027] Example 4 The difference between this embodiment and embodiment 1 is that only M4 is used as a surfactant. This embodiment uses M4 at 6%, 4%, and 3% concentrations to modulate products. The uniformity of the products modulated at the three concentrations does not meet the requirements. The corresponding nickel element concentrations are 82 mg / kg, 90 mg / kg, and 92 mg / kg.

[0028] Embodiment 5:

[0029] The difference between this embodiment and embodiment 1 is that 2% DO46+2% M4 is used as a surfactant. After preparation, the average nickel concentration is measured to be 92 mg / kg, and the lack of uniformity also leads to uneven dissolution.

[0030] In summary, in addition to using an aqueous solution of elemental nickel to prepare a quality control product, the present invention also reasonably selects a combination of surfactants. The combination of Example 1 can meet the requirements of uniformity and stability, and improves the quality of the product.

[0031] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a quality control sample of nickel in lubricating oil, characterized in that: Step 1: Add the antioxidant to the hydrocarbon base oil, heat at 50°C to dissolve, and prepare a uniform solution; Step 2: Take two surfactants, DO-46 and M-4, mix them evenly, add the aqueous nickel metal standard solution, and then add the solution prepared in step 1 to make the volume to the target weight to obtain a prepared quality control sample; Step 3: Stir the prepared quality control sample evenly and store it in aliquots.

2. The method for preparing a quality control sample of nickel in lubricating oil according to claim 1, characterized in that: The antioxidant was T501 antioxidant.

3. The method for preparing a quality control sample of nickel in lubricating oil according to claim 2, characterized in that: Both DO-46 and M-4 surfactants were used at a concentration of 3%.

4. The method for preparing a quality control sample of nickel in lubricating oil according to claim 1, characterized in that: After step one, the method further includes determining the nickel content of the solution prepared in step one and the surfactants DO-46 and M-4 to be used.

5. The method for preparing a quality control sample of nickel in lubricating oil according to claim 1, characterized in that: After step three, the prepared quality control samples are also tested for uniformity and stability.

6. The method for preparing a quality control sample of nickel in lubricating oil according to claim 5, characterized in that: The uniformity test was carried out by inductively coupled plasma optical emission spectroscopy.

7. The method for preparing a quality control sample of nickel in lubricating oil according to claim 1, characterized in that: The nickel content of the quality control sample was 100 mg / kg.

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