Oil fraction extractant

Abstract

Provided is an oil extractant that can be manufactured at low cost, has high oil extraction efficiency, and has a small environmental load, for use in an oil concentration meter or the like. The oil extractant contains an oligomer of a trimer or more of chlorotrifluoroethylene in a range of greater than 35% by weight and 100% by weight or less, relative to the entire oil extractant.

Description

TECHNICAL FIELD

[0001] The present application relates to an oil extractant for extracting oil from a sample. BACKGROUND

[0002] Carbon tetrachloride and tetrachloroethylene, etc., which are used as an oil extractant for extracting oil contained in a sample, are limited when a drug that can affect the environment and / or the human body is manufactured.

[0003] On the other hand, a polymer of a dimer or more of chlorotrifluoroethylene, which is also used as the above-mentioned oil extractant, is not limited.

[0004] In particular, as described in Patent Document 1, the dimer of chlorotrifluoroethylene is known to have high oil extraction efficiency, and thus a substance in which the dimer of chlorotrifluoroethylene is a main component has been used as an oil extractant in the past.

[0005] However, the yield of the dimer obtained by polymerizing a monomer of chlorotrifluoroethylene is low, and thus there is a problem in that the manufacturing cost of the oil extractant can become high.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT DOCUMENTS

[0008] Patent Document 1: Japanese Patent Application Publication No. 2006-145498 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] The present application has been made in view of the above-mentioned problems, and aims to provide an oil extractant that can suppress the manufacturing cost to be lower, has high oil extraction efficiency, and has less environmental load than in the past.

[0011] TECHNICAL SOLUTION

[0012] That is, the oil extractant of the present application is characterized by containing an oligomer of a trimer or more of chlorotrifluoroethylene in a range of greater than 35% by mass and 100% by mass or less.

[0013] If it is such an oil extractant, the yield of the oligomer of a trimer or more at the time of polymerization of a monomer of chlorotrifluoroethylene is higher than the yield of the dimer, and thus the manufacturing cost of the oil extractant can be reduced compared to the past.

[0014] Further, by containing the oligomer of a trimer or more in a range of greater than 35% by mass and 100% by mass or less, the oil extraction efficiency can be further improved compared to the oil extractant of the past.

[0015] Further, since the oligomer having a trimer or more of chlorotrifluoroethylene is contained in a range of more than 35% by weight and 100% by weight or less, compared with the conventional oil extracting agent, it is more difficult to diffuse into the atmosphere, and it is possible to further reduce the environmental load.

[0016] An oil extracting agent characterized by containing an oligomer having a trimer or more of chlorotrifluoroethylene as a main component and having a viscosity of 1.30 cSt or more and 3.00 cSt or less at 25°C. According to the oil extracting agent, the effects of the present application described above can also be obtained.

[0017] In the present specification, the main component means a component having the highest content among the compounds constituting the oil extracting agent. Therefore, the oil extracting agent containing the oligomer having a trimer or more as the main component means not only the oil extracting agent in which one kind of oligomer such as a trimer or a tetramer has the highest content, but also the oil extracting agent in which the total content of all the oligomers having a trimer or more is higher than the content of monomer and dimer.

[0018] As a specific embodiment, an example in which the above oligomer is a trimer can be given.

[0019] A method of detecting the oil concentration of the above oil extracting agent after extracting oil by adding the oil extracting agent to a sample, characterized by using, as the above oil extracting agent, an oil extracting agent containing an oligomer having a trimer or more of chlorotrifluoroethylene in a range of more than 35% by weight and 100% by weight or less. According to the method or the apparatus, it is possible to further suppress the environmental load compared with the conventional one while detecting the oil concentration in the sample at a low cost.

[0020] As a specific embodiment, an example in which the above oil concentration is detected using infrared absorption method can be given.

[0021] A method of producing an oil extracting agent, characterized by polymerizing chlorotrifluoroethylene, removing a substance that hinders oil extraction, and adjusting to contain an oligomer having a trimer or more of chlorotrifluoroethylene in a range of more than 35% by weight and 100% by weight or less. According to the method, the effects of the present application described above can also be obtained.

[0022] Effects of the Invention

[0023] According to the present application, it is possible to provide an oil extracting agent which is low in cost, high in oil extraction efficiency, more difficult to diffuse into the atmosphere compared with the conventional one, and smaller in environmental load.

[0024] Further, since it is more difficult to diffuse into the atmosphere compared with the conventional oil extracting agent, it is also possible to eliminate the loss due to evaporation and suppress the use cost. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic view showing an oil content detection device of one embodiment of the present application.

[0026] Figure 2 is a schematic view showing an oil content meter in the present embodiment.

[0027] Figure 3 is a graph showing experimental results of an embodiment of the present application.

[0028] Figure 4 is a graph showing experimental results of the present embodiment.

[0029] Figure 5 is a graph showing the relationship between the component concentration and the viscosity of the oil content extracting agent.

[0030] Explanation of symbols

[0031] 100... oil content concentration detection device

[0032] 1... oil content meter

[0033] 11... tank

[0034] 12... light source

[0035] 13... light filtering section

[0036] 14... detection section DETAILED DESCRIPTION

[0037] Hereinafter, one embodiment of the present application will be described with reference to the drawings.

[0038] The oil content extracting agent of the present embodiment is an oil content extracting agent that extracts oil content contained in a sample, and is used, for example, in the case of detecting the oil content concentration contained in a sample such as natural water, wastewater from a factory or a sewage treatment plant, or soil.

[0039] As the oil content, there are, for example, petroleum products such as heavy oil, kerosene, gasoline, and light oil, animal oil, vegetable oil, motor oil, and hydrophobic organic solvents.

[0040] The oil content extracting agent contains a dimer of chlorotrifluoroethylene, an oligomer of chlorotrifluoroethylene, a polymer of chlorotrifluoroethylene, and the like, and contains an oligomer of three or more chlorotrifluoroethylene in a range of greater than 35% by weight and 100% by weight or less.

[0041] The oligomer of three or more chlorotrifluoroethylene refers to a polymer of a degree of polymerization of a trimer of three chlorotrifluoroethylene monomers to a decamer of twenty chlorotrifluoroethylene monomers.

[0042] A method of manufacturing the oil content extracting agent will be described below.

[0043] First, the concentration, pressure, temperature, and reaction time are controlled to induce the polymerization reaction of trifluorochloroethylene monomers.

[0044] The resulting polymer contains substances with hydrophilic functional groups generated during the polymerization reaction, which exhibit surface activity and may hinder oil extraction. Therefore, it is purified by using a column, for example, with activated alumina as a support, to remove the substances with hydrophilic functional groups.

[0045] The above-mentioned polymer reactant, from which the hydrophilic functional groups have been removed, is subjected to, for example, distillation to remove the monomers of trifluorochloroethylene and / or polymers of icosemerin or higher as reaction residues, thereby preparing an oligomer of trimer or higher with a content greater than 35% by weight and less than 100% by weight.

[0046] Next, the oil concentration detection device 100, which uses the oil extractant thus manufactured to detect the oil concentration of the sample, will be described.

[0047] like Figure 1 As shown, the oil concentration detection device 100 includes, for example, an extraction tank 2 that contains the oil extractant and the sample and extracts oil from the sample, a stirring member 3 that stirs the oil extractant and the sample contained in the extraction tank 2, an oil concentration meter 1 that detects the concentration of oil extracted through the extraction tank 2 using infrared absorption, and a flow path 4 that connects the extraction tank 2 to the oil concentration meter.

[0048] The extraction tank 2 is, for example, cylindrical, with an injection port 21 formed on its upper part for injecting the oil extractant and the sample.

[0049] The stirring component 3 described above includes, for example, a stirrer 31 driven by a suitable power source, a stirring rod 32 connected to the stirrer 31, and stirring blades 33 mounted on the stirring rod 32.

[0050] The flow path 4 is equipped with a solenoid valve 5 for controlling the flow of liquid supplied from the extraction tank 2 to the oil concentration meter 1, and a filter 6 for removing foreign matter and / or moisture from the liquid supplied to the oil concentration meter 1.

[0051] The filter 6 described above is a mesh filter made of materials such as polytetrafluoroethylene (PTFE).

[0052] like Figure 2As shown in the drawing, the oil concentration meter 1 described above is provided with, for example, a tank 11 that receives the oil extractant from which oil components have been extracted, a light source 12 disposed on one end side of the tank 11, a light filter portion 13 and a detection portion 14 disposed on the other end side of the tank 11, a calculation portion 15 that calculates the oil concentration based on an output value from the detection portion 14, and a display portion (not shown) that displays the oil concentration calculated by the calculation portion 15, and the like.

[0053] The tank 11 described above is in a cylindrical shape including a material having excellent corrosion resistance such as stainless steel, and the openings formed at both end portions thereof are sealed by window members 11A and 11B in a disc shape made of, for example, quartz glass, which has infrared transmittance.

[0054] On the side peripheral surface of the tank 11, a supply port S that supplies the oil extractant and a discharge port D that discharges the oil extractant are provided.

[0055] The light source 12 described above irradiates the one window member 11A of the tank 11 with infrared light along the axial direction of the tank 11.

[0056] The light filter portion 13 described above is a member disposed on the end side of the tank 11 on the side opposite to the light source 12, and is provided with a detection optical filter 13A and a comparison optical filter 13B arranged adjacent to each other in a direction perpendicular to the axial direction of the tank 11.

[0057] These detection optical filter 13A and comparison optical filter 13B are both interference filters (band pass filters) disposed between the tank 11 and the detectors, and are configured to transmit only infrared light in a wave number region of, for example, 2800 to 3100 cm -1 and not transmit infrared light in a wave number region other than this.

[0058] The detection portion 14 described above is a member disposed on the side of the light filter portion 13 opposite to the tank 11, and is provided with a detection detector 14A and a comparison detector 14B.

[0059] These detection detector 14A and comparison detector 14B are both, for example, thermoelectric type infrared sensors, the detection detector 14A described above is disposed downstream of the detection optical filter 13A, and the comparison detector 14B described above is disposed downstream of the comparison optical filter 13B.

[0060] The oil concentration meter 1 described above is further provided with a switching mechanism 16 that switches between the detection detector 14A and the comparison detector 14B described above.

[0061] The switching mechanism 16 is provided with, for example, a chopper 16A disposed between the tank 11 and the light filter portion 13, and a motor 16B that drives the chopper 16A.

[0062] The above light chopper 16A is driven by the above motor 16B, whereby infrared light that has passed through the above tank 11 is intermittently emitted at a predetermined cycle.

[0063] The above calculation section 15 calculates the oil concentration based on the output values from the above detection detector 14A and the above comparison detector 14B, and functions by causing a computer provided with, for example, an amplifier, an A / D converter, a CPU, a memory, a communication port, a display, and the like to operate according to a predetermined program.

[0064] A method for detecting the oil concentration contained in a sample using the above oil extractant and the above oil concentration detection device 100 is as follows.

[0065] First, a sample that is the detection target and the above oil extractant are each weighed in a predetermined amount.

[0066] Next, they are injected from the above injection port into the above stirring layer, and mixed by being sufficiently stirred by the above stirring member 3.

[0067] After the mixed solution is left to separate into a solvent layer containing oil and a water layer, only the above solvent layer is supplied to the above tank 11 via the above flow path.

[0068] There is an absorption specific to a C-H bond in the oil contained in the sample, and therefore, using this property, infrared light is emitted from the above light source 12 to the above tank 11, and the infrared light that has passed through the above tank 11 is detected by the above detection detector 14A and the comparison detector 14B.

[0069] Based on the output values from the detection detector 14A and the comparison detector 14B thus obtained, the above calculation section 15 calculates the oil concentration and outputs it to, for example, the display section provided in the above oil concentration meter 1.

[0070] According to the oil extractant thus configured and the oil concentration detection method or the oil concentration detection device 100 using the same, the following effects can be obtained.

[0071] The yield of the oligomers of trifluorochloroethylene of three or more units is higher than the yield of the dimers when the monomers of trifluorochloroethylene are subjected to a polymerization reaction, and therefore, the manufacturing cost of the above oil extractant can be reduced.

[0072] More specifically, in the case where the monomers of trifluorochloroethylene are subjected to a polymerization reaction, the oligomers of three or more units account for about 80% of the remaining amount with respect to the yield of the dimers, which is about 20%.

[0073] Therefore, compared with the conventional oil extractant in which the dimer of chlorotrifluoroethylene is the main component, the content of the oligomer of three or more chlorotrifluoroethylene can be increased by distillation or the like, and the man-hours can be greatly saved.

[0074] In addition, the oligomer component of three or more chlorotrifluoroethylene, which is discarded in the conventional production of the oil extractant, can be reused, and the reagent can not be wasted, and the load on the environment can be reduced.

[0075] Although the vapor pressure of the dimer of chlorotrifluoroethylene is also low, the vapor pressure of the oligomer component of three or more chlorotrifluoroethylene is lower than that of the dimer of chlorotrifluoroethylene, and therefore the diffusion into the atmosphere when the oil extractant of the present application is used can be further reduced, and the load on the environment can be further reduced.

[0076] The column using activated alumina as a carrier is used to remove substances having a hydrophilic functional group, and therefore substances such as surfactants, which are produced as by-products when the monomer of chlorotrifluoroethylene is subjected to a polymerization reaction, can be removed.

[0077] As a result, when the oil component of the sample is extracted, the water-soluble component can be effectively separated from the oil extractant layer containing the oil component in the sample solution.

[0078] The oil extraction efficiency of the conventional dimer of chlorotrifluoroethylene is also high enough, but by containing the oligomer of three or more chlorotrifluoroethylene at more than 35% by weight and 100% by weight or less, the oil extraction efficiency can be further improved, which is a great achievement in the situation where the development of a new oil extractant is difficult due to the use restrictions of pharmaceuticals.

[0079] In addition, for the oil extractant containing the oligomer of the trimer of chlorotrifluoroethylene at more than 35% by weight and 100% by weight or less and the conventional oil extractant in which the dimer of chlorotrifluoroethylene is the main component, the absorbance at the absorption band specific to the C-H bond (for example, 2941 cm -1 , that is, around 3.4 μm) for oil concentration detection is the same degree, and therefore the oil concentration can be accurately detected by infrared absorption method.

[0080] For the polymer of two or more chlorotrifluoroethylene, there are no problems in that there are no manufacturing restrictions and use restrictions at the time point of December 2017, and therefore it can be used.

[0081] The filter 6 described above uses a mesh filter, and therefore even if the oil extractant in which the oligomer of three or more chlorotrifluoroethylene is the main component and which has a higher viscosity than the conventional one is used, the filter 6 is not easily clogged.

[0082] The present application is not limited to the above-described embodiments.

[0083] For example, the above oil component extracting agent preferably contains the trimer or more and the decamer or less oligomer of the trimer or more of chlorotrifluoroethylene in a range of more than 35% by weight and 100% by weight or less, and more preferably contains the trimer or more and the pentamer or less oligomer of chlorotrifluoroethylene in a range of more than 35% by weight and 100% by weight or less.

[0084] In addition, the range of the content ratio of the trimer or more oligomer is not limited to the above range, and can be more than 35.00% by weight and 51.25% by weight or less, more than 35.00% by weight and 67.50% by weight or less, more than 35.00% by weight and 83.75% by weight or less, 51.25% by weight or more and 67.50% by weight or less, 51.25% by weight or more and 83.75% by weight or less, 51.25% by weight or more and 100.00% by weight or less, 67.50% by weight or more and 83.75% by weight or less, 67.50% by weight or more and 100.00% by weight or less, 83.75% by weight or more and 100.00% by weight or less, or the like.

[0085] The content of the trimer or more oligomer of chlorotrifluoroethylene is not limited to the above range, and the viscosity of the oil component extracting agent at 25°C is preferably 1.300 cSt or more and 3.00 cSt or less, and more preferably 1.40 cSt or more and 2.80 cSt or less, with the trimer or more oligomer of chlorotrifluoroethylene as a main component, and if it is such an oil component extracting agent, the same effects as described above can be obtained.

[0086] If the trimer or more oligomer of chlorotrifluoroethylene is used, the viscosity becomes higher compared to the case where the dimer or more oligomer is used. In particular, in the flow path type oil component concentration detecting device in which the oil component extracting agent from which the oil component has been extracted is supplied to the tank via the flow path as described in the present embodiment, it is considered that if the viscosity of the oil component extracting agent is high, the response becomes late.

[0087] Therefore, if the trimer or more of chlorotrifluoroethylene is contained in an amount of 65% by weight or more, the response in the flow path type oil component concentration detecting device described above is fast, and thus it is preferable.

[0088] In the above embodiment, a method and a device for detecting the oil component concentration using infrared light are described, but it is not limited thereto, and the oil component can be detected using the gravimetric method and / or the microbalance method, or the like.

[0089] As a method for removing the above substance having a hydrophilic functional group, not only a method using a column with activated alumina as a carrier, but also a method for removing impurities using the solubility of water-soluble impurities and / or the salting-out effect by mixing with water and / or a saturated sodium chloride aqueous solution, filtration using activated alumina and / or silica gel, distillation, or the like can be used.

[0090] In addition, the oil extractant described above can be used not only for detecting the concentration of oil contained in a sample, but also for a cleaning process for removing oil from various devices, components, and pipes, and the like.

[0091] In the embodiment described above, the oil concentration detection device 100 includes the extraction tank 2 and the like, but the oil concentration detection device 100 can include only the oil concentration meter 1, or can further include other components in addition to the oil concentration meter 1, depending on the use environment and / or the shape of the sample from which oil is extracted, and the like.

[0092] For example, the oil concentration detection device 100 can not include the extraction tank 2, and can extract oil from a sample by placing the oil extractant and the sample in a separatory funnel and / or a container such as a bottle with a cap, and shaking and mixing the contents using a shaker. The oil can also be extracted by a method of shaking and mixing the contents using a hand-held separatory funnel and the like, without using a shaker and the like.

[0093] In this case, a mesh filter formed of a material such as polytetrafluoroethylene (PTFE) can be used instead of the filter to remove foreign matter and / or moisture.

[0094] As for the method of supplying the oil extractant from which oil has been extracted to the tank 11, the oil extractant can be supplied via a flow path, or the oil extractant from which oil has been extracted can be directly injected into the tank 11.

[0095] The supply port S and the discharge port D formed in the tank 11 can be formed as one and the same opening.

[0096] The oil extractant of the present application can extract not only various oils described above, but also, for example, organic compounds having a hydrocarbon group such as benzene and amine, and compounds that are nonpolar as molecules, such as iodine, carbon tetrachloride, and tetrachloroethylene.

[0097] In addition, various modifications and combinations of embodiments can be made without departing from the spirit of the present application.

[0098] Embodiment

[0099] In the following, the oil extractant of the present application will be further described in detail with reference to an embodiment, but the present application is not limited to this embodiment.

[0100] In this embodiment, the oil extraction efficiency of the oil extractant A and the oil extractants S1 to S8 obtained by varying the content of the oligomers of the trimer or more of chlorotrifluoroethylene were compared.

[0101] As the oil extractant of the past, the oil extractant A containing the oligomers of the dimer of chlorotrifluoroethylene in the range of 65% by weight or more and 75% by weight or less and containing the oligomers of the trimer or more of chlorotrifluoroethylene in the range of 25% by weight or more and 35% by weight or less was used.

[0102] The monomer of chlorotrifluoroethylene was subjected to a polymerization reaction, and after removing impurities with an activated alumina column, the chlorotrifluoroethylene was refined by distillation so that only the trimer of chlorotrifluoroethylene or the tetramer of chlorotrifluoroethylene reached 99.9%.

[0103] The trimer or tetramer of chlorotrifluoroethylene was mixed with the oil extractant A in the proportions described in Table 1 below to produce the oil extractants S1 to S8 obtained by varying the content of the oligomers of the trimer or more of chlorotrifluoroethylene.

[0104] [Table 1]

[0105] Trimer Tetramer Oil extractant A R 0 0 100 S1 25 0 75 S2 50 0 50 S3 75 0 25 S4 100 0 0 S5 0 25 75 S6 0 50 50 S7 0 75 25 S8 0 100 0

[0106] For the eight oil extractants, the oil extraction efficiency was detected as follows, respectively.

[0107] As the object of the oil extraction, simulated oil water containing 100 mg / L of oil (B heavy oil) was used.

[0108] For the simulated oil water, as in the contents described in the above embodiment, in this embodiment, the oil extraction was performed in the above extraction tank 2 attached to the above oil concentration detection device 100 with a certain amount of the simulated oil water and the oil extractant being stirred for 40 seconds in the mixing time.

[0109] Note that, in order to minimize the error due to the detection error and / or the deviation of the operation time as much as possible, R which is only the oil extractant A as the oil extractant of the past was operated at the same time as the other samples.

[0110] Then, the oil concentration extracted with each oil extractant was detected, and the results of checking the consistency with the actual oil concentration of the above simulated oil water are Table 2, Table 3, Figure 3 and Figure 4 .

[0111] Table 2 and Figure 3 Table 3 below show the oil extraction efficiency of S1 to S4 in the case where the oil extraction efficiency of R which is the oil extractant of the past is set to 100%.

[0112] Table 2

[0113]

[0114] In addition, Table 3 and Figure 4 The oil component extraction efficiency of each of S5 to S8 is shown in the case where the oil component extraction efficiency of R, which is a conventional oil component extraction agent, is set to 100%.

[0115] Table 3

[0116]

[0117] From these Tables 2, 3, Figure 3 and Figure 4 As a result, it was found that, as the oil component extraction agent containing the oligomer of the trimer or more of chlorotrifluoroethylene in the range of more than 35% by weight and 100% by weight or less, the oil component extraction efficiency is greatly improved compared to the conventional oil component extraction agent.

[0118] Note that, not limited to the trimer and the tetramer described above, in the case where the pentamer and / or the hexamer of chlorotrifluoroethylene or the like is mixed with the conventional oil component extraction agent A, and the content of the oligomer of the trimer or more is set to be more than 35% by weight and 100% by weight or less, the oil component extraction efficiency can be greatly improved compared to the conventional oil component extraction agent.

[0119] It was found that the extraction efficiency of the oil component extraction agent containing the oligomer of the trimer or more of chlorotrifluoroethylene in the range of more than 67.85% by weight and 83.75% by weight or less shows particularly high extraction efficiency compared to the conventional oil component extraction agent.

[0120] It is considered that the reason why the oil component extraction agent using the content of the oligomer of the trimer or more more than the conventional one improves the extraction efficiency is that the oil component extraction performance of the oil component extraction agent including various molecular structures becomes high.

[0121] In addition, from the results of the examples, it was found that, by setting the content of the oligomer of the trimer or the tetramer of chlorotrifluoroethylene to be 65% by weight or more, a sufficiently high oil component extraction efficiency can be obtained compared to the conventional oil component extraction agent. Therefore, by setting the content of the oligomer of the trimer or the tetramer of chlorotrifluoroethylene to be 65% by weight or more, even if a difference of ±10% to 20% in the oil component extraction performance is generated for each batch of products, the oil component extraction efficiency can be sufficiently maintained compared to the conventional oil component extraction agent in which the dimer is the main component.

[0122] It has been conventionally believed that if the content of the oligomer of the trimer or more of chlorotrifluoroethylene becomes high, the content of impurities such as a substance similar to a surfactant produced as a byproduct of the polymerization reaction also becomes high.

[0123] It is considered that the reason is that if the polymerization degree is high, a cyclic or branched compound is easily produced, and among them, a substance having both a hydrophilic group and a hydrophobic group is easily produced.

[0124] If the content of the above-mentioned impurities becomes high, the separation of the layer of the sample and the oil extractant becomes slow, and thus the analysis takes time. For example, if the content of the above-mentioned impurities becomes 10 mg / L or more, the layer separation takes 10 minutes or more.

[0125] In addition, due to the mixing of the above-mentioned impurities, water is easily mixed into the oil extractant, and as a result, there is also a problem that the detection value of the infrared absorption by the above-mentioned oil concentration detection device is easily unstable.

[0126] However, contrary to the above-mentioned conventional technical common sense, for each of the oil extractants S1 to S8 of the present embodiment, which are mainly composed of the oligomer of the trimer or more of chlorotrifluoroethylene, the content of the above-mentioned impurities is in a range where there is absolutely no problem in the layer separation and / or the detection of the infrared absorption.

[0127] It is considered that this is because the method of removing the above-mentioned impurities by filtration using activated alumina can sufficiently lower the concentration of the above-mentioned impurities.

[0128] Further, conventionally, if the oligomer of the trimer or more of chlorotrifluoroethylene is used, the peak of the infrared absorption becomes wide, and thus the baseline of the absorbance becomes high, and the oil concentration cannot be correctly detected.

[0129] However, it is known that for the oil extractants S1 to S8, the peak of the infrared absorption can be sufficiently used for the detection of the oil concentration. In addition, the higher the boiling point of the oil extractant, the smaller the infrared absorption, and thus it is more advantageous that the content of the oligomer of the trimer or more of chlorotrifluoroethylene is high.

[0130] Further, the absorption of the infrared light depending on the content of the oligomer of the trimer or more of chlorotrifluoroethylene of the oil extractant was investigated in detail, and as a result, it was found that even if the oligomer of the hexamer or more of chlorotrifluoroethylene is contained, it can also be sufficiently used for the detection of the oil concentration, and as the polymerization degree decreases from the pentamer, the tetramer, and the trimer, the transmittance of the infrared light becomes high, and the baseline of the infrared absorption is clearly drawn. It is known that there is a difference of about 5% or so in the transmittance of the infrared light between the oligomer of the pentamer and the oligomer of the trimer.

[0131] However, the oil extractant having the oligomer of the trimer or more of chlorotrifluoroethylene as a main component has a tendency that the viscosity of the oil extractant becomes higher as the content of the trimer or more of chlorotrifluoroethylene increases.

[0132] For example, as shown in Figure 5 , it is known that the content of the trimer of chlorotrifluoroethylene and the viscosity are in a proportional relationship.

[0133] According to the Figure 5 , it is known that the viscosity at 25°C is about 1.55 cSt when the content of the trimer of chlorotrifluoroethylene is 35%, and the viscosity at 25°C is about 2.55 cSt when the content of the trimer of chlorotrifluoroethylene is 100%.

[0134] Since the properties of the oil extractant manufactured in each batch of products vary as described above, if the variation is set to about ±20%, it is considered that the viscosity of the oil extractant manufactured in a case where the content of the trimer of chlorotrifluoroethylene is 35% or more and 100% or less is in a range of 1.30 cSt or more and 3.00 cSt or less at 25°C.

[0135] Therefore, it is considered that the oil extractant having the oligomer of the trimer or more of chlorotrifluoroethylene as a main component and having a viscosity in a range of 1.30 cSt or more and 3.00 cSt or less at 25°C can also exhibit a higher oil extractability than the oil extractants shown in Table 2 and Figure 3 , as described above.

[0136] The results of the case found by the experiment are shown in Table 4. Table 4 shows the results obtained by using two kinds of oil extractants having the oligomer of the trimer or more of chlorotrifluoroethylene as a main component and having a viscosity in the above range to extract various oil components.

[0137]

Table 4

[0138] 2.6 cSt 2.0 cSt B heavy oil 23.5 24.0 Triolein 37.1 34.6 Engine oil 62.3 59.2 OCB 37.2 47.8 Light oil 63.4 63.6 Vegetable oil 45.5 45.7 A heavy oil 54.5 51.0 Arabian light oil 22.3 19.8

[0139] In this experiment, the oil components in the simulated oil water were extracted in the same procedure as in the case of Table 2 and Table 3 described above using the oil extractants having the oligomer of the trimer or more of chlorotrifluoroethylene as a main component and having a viscosity of about 2.6 cSt or about 2.0 cSt at 25°C. Each number in Table 4 indicates the concentration of the oil component extracted from the simulated oil water containing each oil at a concentration of 100 mg / L using the oil extractant (unit: mg / L). OCB in Table 4 means a mixture of octane, hexadecane, and benzene. It should be noted that the oil extractant having a viscosity of about 2.6 cSt at 25°C corresponds to S4 shown in Table 1 and Table 2, which has a higher oil extractability than the conventional one.

[0140] From the results of this Table 4, it is understood that if the oil component extraction agent is an oligomer of trifluorochloroethylene having a degree of polymerization of three or more and has a kinematic viscosity at 25°C in the range of 1.30 cSt or more and 3.00 cSt or less, it can exhibit sufficiently high oil component extraction ability for various oil components.

Claims

1. An oil fraction extracting agent characterized by comprising: An oligomer containing a trimer or more and a pentamer or less of chlorotrifluoroethylene and containing a tetramer, the total content of the oligomer of the trimer or more and the pentamer or less and the oligomer of the tetramer being in a range of more than 35% by weight and 100% by weight or less, the content of the oligomer of the trimer or the tetramer being 65% by weight or more, and the content of impurities produced as a by-product of a polymerization reaction being less than 10 mg / L.

2. The oil component extracting agent according to claim 1, wherein The viscosity at 25°C is 1.30 cSt or more and 3.00 cSt or less.

3. The oil fraction extracting agent according to claim 1 or 2, characterized in that, The oligomer of the trimer or more and the pentamer or less of chlorotrifluoroethylene is an oligomer of the tetramer.

4. An oil concentration detection method characterized by comprising: The oil component concentration of the oil component extracting agent after the oil component has been extracted is detected by adding the oil component extracting agent to a sample, As the oil component extracting agent, an oil component extracting agent containing an oligomer of a trimer or more and a pentamer or less of chlorotrifluoroethylene and containing a tetramer, the total content of the oligomer of the trimer or more and the pentamer or less and the oligomer of the tetramer being in a range of more than 35% by weight and 100% by weight or less, the content of the oligomer of the trimer or the tetramer being 65% by weight or more, and the content of impurities produced as a by-product of a polymerization reaction being less than 10 mg / L is used.

5. The oil dilution concentration detection method according to claim 4, characterized by, The oil component concentration is detected using infrared absorption.

6. An oil concentration detecting device characterized by comprising: The oil component concentration of the oil component extracting agent after the oil component has been extracted is detected by adding the oil component extracting agent to a sample, As the oil component extracting agent, an oil component extracting agent containing an oligomer of a trimer or more and a pentamer or less of chlorotrifluoroethylene and containing a tetramer, the total content of the oligomer of the trimer or more and the pentamer or less and the oligomer of the tetramer being in a range of more than 35% by weight and 100% by weight or less, the content of the oligomer of the trimer or the tetramer being 65% by weight or more, and the content of impurities produced as a by-product of a polymerization reaction being less than 10 mg / L is used.

7. The oil dilution concentration detection device according to claim 6, characterized by A tank that receives the oil component extracting agent after the oil component has been extracted, an infrared light source disposed on one end side of the tank, and an optical filter and an infrared light detector disposed on the other end side of the tank are provided.

8. A method for producing an oil fraction extracting agent, characterized by, Chlorotrifluoroethylene is polymerized, a substance that hinders the extraction of an oil component is removed so that the content of impurities produced as a by-product of a polymerization reaction is less than 10 mg / L, an oligomer containing a trimer or more and a pentamer or less of chlorotrifluoroethylene and containing a tetramer is adjusted, the total content of the oligomer of the trimer or more and the pentamer or less and the oligomer of the tetramer being in a range of more than 35% by weight and 100% by weight or less, and the content of the oligomer of the trimer or the tetramer being 65% by weight or more.

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