Hydrogenated terphenyl high-temperature heat transfer oil and preparation method thereof

Abstract

The application relates to the field of heat conducting oil, and discloses a hydrogenated terphenyl type high-temperature heat conducting oil and a preparation method thereof. The heat conducting oil contains dicyclohexylbenzene, cyclohexylbiphenyl and terphenyl, and the content of the cyclohexylbiphenyl in the heat conducting oil is not less than 40% by weight. In the application, the solid acid catalyst is used to perform an alkylation reaction on cyclohexylbenzene, cyclohexene and / or cyclohexanol, then the product is separated, and then the separated product is subjected to a partial dehydrogenation reaction through a dehydrogenation catalyst, so that the yield of the hydrogenated terphenyl is high, the preparation process is simple, the energy consumption is low, the stability is good, and the product meets the corresponding requirements in the national standard.

Description

Technical Field

[0001] This invention relates to the field of heat transfer oils, specifically to a hydrogenated terphenyl-type high-temperature heat transfer oil and its preparation method. Background Technology

[0002] Hydrogenated terphenyl, as a synthetic high-temperature heat transfer medium, is widely used in industries such as petroleum and petrochemicals, chemicals, synthetic fibers, papermaking, textiles, food, and solar thermal energy. In existing technologies, the preparation of hydrogenated terphenyl typically involves high-temperature condensation of benzene to obtain terphenyl; the mixture obtained after partial hydrogenation of the terphenyl is the desired hydrogenated terphenyl heat transfer oil. In this route, terphenyl is a byproduct of biphenyl production; therefore, the yield of terphenyl determines the economics and energy and material consumption of the benzene process. As a byproduct, terphenyl has a low yield, resulting in high energy consumption throughout the entire route. In recent years, with the large-scale investment in photovoltaic power generation and air energy storage projects, the market demand for hydrogenated terphenyl-based high-temperature heat transfer oils has been increasing. Therefore, developing new low-energy-consumption technologies, improving the yield of hydrogenated terphenyl, and preparing hydrogenated terphenyl heat transfer oils with high thermal stability are of great significance for the wider application of hydrogenated terphenyl-based high-temperature heat transfer oils. Summary of the Invention

[0003] The purpose of this invention is to overcome the problems of low yield, high energy consumption in preparation, and poor thermal stability of hydrogenated terphenyl in the existing technology, and to provide a hydrogenated terphenyl heat transfer oil and its preparation method.

[0004] To achieve the above objectives, the present invention provides a hydrogenated terphenyl type high-temperature heat transfer oil, which contains: dicyclohexylbenzene, cyclohexylbiphenyl and terphenyl, and the content of cyclohexylbiphenyl in the heat transfer oil is not less than 40% by weight.

[0005] Another aspect of the present invention provides a method for preparing a hydrogenated terphenyl-type high-temperature heat transfer oil, the method comprising the following steps:

[0006] (1) Cyclohexylbenzene is reacted with cyclohexene and / or cyclohexanol by alkylation under the action of a solid acid catalyst to generate a mixture containing dicyclohexylbenzene;

[0007] (2) Remove the C6-C12 components from the mixture containing dicyclohexylbenzene to obtain dicyclohexylbenzene;

[0008] (3) Partial dehydrogenation of dicyclohexylbenzene under the action of a dehydrogenation catalyst yields hydrogenated terphenyl-type high-temperature heat transfer oil.

[0009] This invention employs a solid acid catalyst to carry out an alkylation reaction of cyclohexylbenzene with cyclohexene and / or cyclohexanol, followed by separation and partial dehydrogenation reaction via a dehydrogenation catalyst. This results in a high yield of hydrogenated terphenyl, low energy consumption in the preparation process, and the product meets the relevant requirements stipulated in national standards. Detailed Implementation

[0010] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0011] The present invention provides a hydrogenated terphenyl type high-temperature heat transfer oil, which contains dicyclohexylbenzene, cyclohexylbiphenyl and terphenyl, and the content of cyclohexylbiphenyl in the heat transfer oil is not less than 40% by weight.

[0012] According to a preferred embodiment of the present invention, the total amount of dicyclohexylbenzene, cyclohexylbiphenyl and terphenyl in the hydrogenated terphenyl-type high-temperature heat transfer oil is not less than 70% by weight, preferably not less than 80% by weight.

[0013] According to a preferred embodiment of the present invention, the content of cyclohexylbiphenyl is not less than 45% by weight, preferably 45-55% by weight. This preferred embodiment is more conducive to improving the thermal oxidative stability of the components in the product and extending its lifespan.

[0014] According to a preferred embodiment of the present invention, the heat transfer oil contains 5-60% by weight of dicyclohexylbenzene, 40-80% by weight of cyclohexylbiphenyl, and 1-30% by weight of terphenyl; more preferably, the heat transfer oil contains 10-40% by weight of dicyclohexylbenzene, 45-55% by weight of cyclohexylbiphenyl, and 5-20% by weight of terphenyl. The hydrogenated terphenyl-type high-temperature heat transfer oil of the present invention preferably contains a high content of cyclohexylbiphenyl, and preferably contains specific amounts of dicyclohexylbenzene, cyclohexylbiphenyl, and terphenyl, making the product composition richer. The multi-component combination gives the hydrogenated terphenyl heat transfer oil advantages such as low pour point, good thermal stability, and low degradation rate.

[0015] According to the present invention, any heat transfer oil that meets the foregoing requirements can be used in the present invention, and there are no special requirements for the source of each component. For the present invention, it is preferred that the dicyclohexylbenzene is derived from the alkylation reaction of cyclohexylbenzene with cyclohexene and / or cyclohexanol; it is also preferred that the cyclohexylbiphenyl and terphenyl are derived from the dehydrogenation reaction of dicyclohexylbenzene. This preferred embodiment can effectively reduce energy consumption, giving the hydrogenated terphenyl heat transfer oil of the present invention the advantages of wide availability and low cost.

[0016] Another aspect of the present invention provides a method for preparing a hydrogenated terphenyl-type high-temperature heat transfer oil, the method comprising the following steps:

[0017] (1) Cyclohexylbenzene is reacted with cyclohexene and / or cyclohexanol by alkylation under the action of a solid acid catalyst to generate a mixture containing dicyclohexylbenzene;

[0018] (2) Remove the C6-C12 components from the mixture containing dicyclohexylbenzene to obtain dicyclohexylbenzene;

[0019] (3) Partial dehydrogenation of dicyclohexylbenzene under the action of a dehydrogenation catalyst yields hydrogenated terphenyl-type high-temperature heat transfer oil.

[0020] This invention employs a solid acid catalyst to alkylate cyclohexylbenzene with cyclohexene and / or cyclohexanol, followed by separation and dehydrogenation via a dehydrogenation catalyst. This results in a high yield of hydrogenated terphenyl. Compared to the existing high-temperature pyrolysis method for preparing hydrogenated terphenyl, this invention significantly reduces material and energy consumption during the reaction process, minimizes compositional differences between products, and enhances the stability of industrial production.

[0021] According to the present invention, preferably, the solid acid catalyst comprises a mesoporous molecular sieve and / or a heteropoly acid and a binder.

[0022] In this invention, the use of mesoporous molecular sieves and / or heteropoly acids in the solid acid catalyst can achieve the objective of the invention. Preferably, the solid acid catalyst comprises an acidic mesoporous molecular sieve, a heteropoly acid, and a binder. This preferred embodiment is more conducive to the alkylation reaction between cyclohexylbenzene molecules and cyclohexene / cyclohexanol, improves the diffusion of macromolecules of the reaction products, and avoids excessive carbon deposition that could lead to catalyst deactivation.

[0023] According to the present invention, preferably, the mesoporous molecular sieve is a mesoporous molecular sieve of type MWW, FAU, or BEA, specifically selected from at least one of mesoporous MWW-22 molecular sieve, mesoporous Y-type molecular sieve, and mesoporous beta molecular sieve, and more preferably mesoporous MWW-22 molecular sieve and / or mesoporous Y-type molecular sieve. The molecular sieve raw powders MWW-22, beta, and Y molecular sieve used in the present invention are all commercially available or can be synthesized in the laboratory. For mesoporous MWW and mesoporous beta molecular sieves, they are obtained by alkaline treatment; for mesoporous Y-type molecular sieves, they are obtained by hydrothermal treatment. The alkaline treatment or hydrothermal treatment methods used are conventional techniques in the field of molecular sieves and do not require special explanation. For example, the mesoporous MWW and mesoporous beta molecular sieves have a silica-to-alumina ratio between 30 and 40 and a mesopore volume between 0.2 and 0.4 cm³. 3 / g; the mesoporous Y molecular sieve has a silica-to-alumina ratio between 10 and 20, and a mesopore volume between 0.2 and 0.4 cm³. 3 / g. This preferred embodiment is more conducive to improving the reactivity and diffusion capacity of the molecular sieve.

[0024] According to the present invention, the heteropolyacid is preferably a phosphotungstic acid type heteropolyacid, specifically preferably selected from phosphomolybdic acid and / or phosphotungstic acid, and more preferably phosphotungstic acid. The solid acid catalyst prepared using phosphotungstic acid exhibits higher cyclohexene conversion and dicyclohexylbenzene selectivity in the alkylation reaction of cyclohexylbenzene and cyclohexene, further contributing to improved yield of hydrogenated terphenyl.

[0025] According to the present invention, the range of the adhesives is relatively wide. Preferably, the adhesive is selected from at least one of alumina, silica, clay and diatomaceous earth, and more preferably alumina.

[0026] According to the present invention, preferably, based on the total amount of the solid acid catalyst, the content of mesoporous molecular sieve and / or heteropoly acid is 50-70% by weight, and the content of binder is 30-50% by weight; more preferably, the content of mesoporous molecular sieve and / or heteropoly acid is 60-70% by weight, and the content of binder is 30-40% by weight.

[0027] The present invention does not particularly limit the preparation method of the solid acid catalyst, as long as the above-mentioned alkylation reaction can be carried out, any method known in the art can be used.

[0028] According to a preferred embodiment of the present invention, when the solid acid catalyst comprises a mesoporous molecular sieve and a binder, the preparation method of the solid acid catalyst includes: kneading the mesoporous molecular sieve and the binder into a mold, then drying and calcining; finally, subjecting the calcined product to ammonium exchange. The drying, calcination, and ammonium exchange can all be carried out under conventional conditions. Preferably, the drying includes drying at 100-150°C for 5-24 hours. Preferably, the calcination includes calcining at 450-650°C for 3-8 hours. Preferably, the ammonium exchange includes: exchanging the calcined product with an ammonium salt solution at 40-100°C for 1-24 hours, washing with deionized water, drying at 100-150°C for 5-24 hours, and calcining at 450-650°C for 3-8 hours. Preferably, the ammonium salt solution comprises an aqueous solution prepared from one or any combination of ammonium nitrate, ammonium chloride, ammonium sulfate, and ammonium oxalate with deionized water. In the preparation process of the solid acid catalyst, the shaped sample can also be air-dried at room temperature and pressure for 1-24 hours before drying.

[0029] According to a preferred embodiment of the present invention, when the solid acid catalyst comprises a heteropoly acid and a binder, the preparation method of the solid acid catalyst includes: kneading the heteropoly acid and the binder into a mold, and then drying and calcining. Preferably, the drying includes drying at 100-150°C for 5-24 hours. Preferably, the calcination includes calcining at 350-550°C for 3-8 hours. During the preparation of the solid acid catalyst, the molded sample may also be air-dried at room temperature and pressure for 1-24 hours before drying.

[0030] According to the present invention, the solid acid catalyst can take any physical form, such as powder, granules, or molded form, such as spheres, flakes, strips, or clover shapes; preferably spheres or strips. These physical forms can be obtained in any manner conventionally known in the art, and there are no particular limitations.

[0031] According to the present invention, in the preparation of hydrogenated terphenyl heat transfer oil, preferably, the alkylation reaction conditions include: a reaction temperature of 80-200°C, a reaction pressure of 0.8-3.0 MPa, a molar ratio of cyclohexylbenzene to cyclohexene and / or cyclohexanol of 1-6:1, and a mass hourly space velocity (HHSV) of cyclohexene and / or cyclohexanol of 0.1-2.0 h⁻¹. -1 Specifically, for example, the reaction temperature is preferably 150-190°C; the reaction pressure is preferably 1.0-2.5 MPa; the molar ratio of cyclohexylbenzene to cyclohexene and / or cyclohexanol is preferably 2-5:1; and the mass hourly space velocity (HSV) of cyclohexene and / or cyclohexanol is preferably 0.8-1.5 h⁻¹. -1 .

[0032] According to the present invention, there are no particular limitations on the method for removing the C6-C12 components from the mixture containing dicyclohexylbenzene in step (2). Preferably, vacuum distillation is used to remove the C6-C12 components from the mixture containing dicyclohexylbenzene. The C6-C12 components mainly include cyclohexene / cyclohexanol and cyclohexylbenzene, and small amounts of methylcyclopentane, etc.

[0033] According to a preferred embodiment of the present invention, the conditions for vacuum distillation include: a temperature of 220-300°C and a vacuum degree of 2-10 kPa. Specifically, for example, the temperature can preferably be 240-290°C; and the vacuum degree can preferably be 3-5 kPa.

[0034] According to the present invention, the selection range of the dehydrogenation catalyst is relatively wide, as long as it can achieve the dehydrogenation of dicyclohexylbenzene. Preferably, the dehydrogenation catalyst comprises a support and a dehydrogenation metal.

[0035] According to a preferred embodiment of the present invention, the carrier is selected from at least one of alumina and silicon oxide.

[0036] According to a preferred embodiment of the present invention, the dehydrogenating metal is selected from at least one of Group VIII non-noble metals and / or at least one of noble metals, wherein the noble metal has the conventional meaning in the art, and the noble metal is selected from at least one of gold, silver, and platinum group metals (ruthenium, rhodium, palladium, osmium, iridium, platinum). Further, the dehydrogenating metal may preferably be at least one of Ni, Pt, and Pd.

[0037] According to a preferred embodiment of the present invention, the content of the support in the dehydrogenation catalyst is 85-99% by weight, and the content of the dehydrogenation metal is 1-15% by weight, based on the total amount of the dehydrogenation catalyst. More preferably, the content of the support is 87-98% by weight, and the content of the dehydrogenation metal is 2-13% by weight, based on the total amount of the dehydrogenation catalyst.

[0038] This invention does not particularly limit the preparation method of the dehydrogenation catalyst; for example, it can be a conventional impregnation method. Specifically, it preferably includes: loading the metal active component onto an alumina support in the form of a precursor salt solution, optionally drying it at room temperature and pressure for 1-24 hours, followed by drying and calcination. The drying preferably includes drying at 100-150°C for 5-24 hours, and the calcination preferably includes calcining at 450-650°C for 3-8 hours. Before use, the dehydrogenation catalyst also includes reduction, preferably carried out under a hydrogen atmosphere at a reduction temperature of 100-500°C for 0.5-12 hours and a hydrogen volume hourly space velocity of 100-600 h⁻¹. -1 The precursor salt can be at least one of the water-soluble compounds corresponding to dehydrogenated metals. The present invention does not have any particular limitation on this, and those skilled in the art can make appropriate selections.

[0039] According to a preferred embodiment of the invention, the dehydrogenation catalyst can be in any physical form, such as powder, granules, or molded form, such as spheres, flakes, strips, or clover shapes; preferably spheres or strips. These physical forms can be obtained in any manner conventionally known in the art, and there is no particular limitation.

[0040] According to a preferred embodiment of the present invention, the conditions for the partial dehydrogenation include: a reaction temperature of 300-450°C, a molar ratio of hydrogen to dicyclohexylbenzene of 0.1-30, and a mass hourly space velocity (HHSV) of 0.1-2.0 h⁻¹. -1Specifically, for example, the reaction temperature is preferably 320-400℃; the molar ratio of hydrogen to dicyclohexylbenzene is preferably 0.5-20:1. Under these preferred conditions, it is beneficial to improve catalyst lifetime and prevent rapid catalyst deactivation due to carbon buildup. The mass hourly space velocity (HSV) of dicyclohexylbenzene is preferably 0.8-1.5 h⁻¹. -1 .

[0041] The preparation process of the hydrogenated terphenyl high-temperature heat transfer oil of the present invention is simple and energy-efficient. In actual industrial production, the product composition varies little and the stability is good. It can obtain hydrogenated terphenyl heat transfer oil with excellent high-temperature resistance and can replace traditional hydrogenated terphenyl products.

[0042] The advantages of the present invention are described in detail below through examples, but are not limited to the scope of protection of the present invention.

[0043] The following preparation examples illustrate the preparation of solid acid catalysts.

[0044] The molecular sieve raw materials MWW-22, beta, and Y molecular sieves were all purchased commercially.

[0045] Preparation Example 1-1

[0046] Take 60 g of mesoporous MWW-22 molecular sieve powder, then take 40 g of alumina to compound it together, knead and shape it into strips, dry at 120℃ for 12 hours, and then calcine at 400℃ for 5 hours. Exchange the above-shaped sample with ammonium chloride solution at 80℃ for 8 hours, wash with deionized water, dry at 150℃ for 5 hours, and calcine at 500℃ for 6 hours. The desired solid acid catalyst G1 is obtained.

[0047] Preparation Examples 1-2

[0048] Take 60 g of mesoporous beta molecular sieve powder, then take 40 g of alumina and combine them together. Knead and shape into strips, dry at 120°C for 12 hours, and then calcine at 400°C for 5 hours. Exchange the above-shaped sample with ammonium chloride solution at 80°C for 8 hours, wash with deionized water, dry at 150°C for 5 hours, and calcine at 500°C for 6 hours. The desired solid acid catalyst G2 is obtained.

[0049] Preparation Examples 1-3

[0050] Take 60 g of mesoporous Y molecular sieve powder, then take 40 g of alumina and combine them together. Knead and shape into strips, dry at 120℃ for 12 hours, and then calcine at 400℃ for 5 hours. Exchange the above-shaped sample with ammonium chloride solution at 80℃ for 8 hours, wash with deionized water, dry at 150℃ for 5 hours, and calcine at 500℃ for 6 hours. The desired solid acid catalyst G3 is obtained.

[0051] Preparation Examples 1-4

[0052] Take 30g of mesoporous MWW-22 molecular sieve powder and 30g of mesoporous beta molecular sieve powder, then add 40g of alumina and combine them together. Knead the mixture, shape it into strips, dry it at 120℃ for 12 hours, and then calcine it at 400℃ for 5 hours. Exchange the above-shaped sample with ammonium chloride solution at 80℃ for 8 hours, wash it with deionized water, dry it at 150℃ for 5 hours, and calcine it at 500℃ for 6 hours. The desired solid acid catalyst G4 is obtained.

[0053] Preparation Examples 1-5

[0054] Take 60 grams of phosphotungstic acid powder, then take 40 grams of alumina and combine them together, knead and shape into strips, dry at 120°C for 12 hours, and then calcine at 400°C for 5 hours. The desired solid acid catalyst G5 is obtained.

[0055] Preparation Examples 1-6

[0056] Take 70 grams of phosphotungstic acid powder, then take 30 grams of alumina and combine them together, knead, shape into strips, dry at 120°C for 12 hours, and then calcine at 400°C for 5 hours. The desired solid acid catalyst G6 is obtained.

[0057] Preparation Examples 1-7

[0058] Take 35 grams of phosphotungstic acid powder and 35 grams of phosphomolybdic acid powder, then take 30 grams of alumina and combine them together, knead, shape into strips, dry at 120°C for 12 hours, and then calcine at 400°C for 5 hours. The desired solid acid catalyst G7 is obtained.

[0059] The following preparation examples illustrate the preparation of dehydrogenation catalysts.

[0060] Preparation Example 2-1

[0061] 100 g of alumina support was loaded with 3 g of Pt and dried at 120 °C for 12 hours, followed by calcination at 550 °C for 5 hours. The resulting sample was then reduced at 450 °C for 6 hours at a hydrogen hourly space velocity (HHSV) of 300 h⁻¹. -1 The desired dehydrogenation catalyst H1 is thus obtained.

[0062] Preparation Example 2-2

[0063] 100 g of alumina support was loaded with 5 g of Pt and dried at 120 °C for 12 hours, followed by calcination at 550 °C for 5 hours. The resulting sample was then reduced at 450 °C for 6 hours at a hydrogen hourly space velocity (HHSV) of 300 h⁻¹. -1 The desired dehydrogenation catalyst H2 is thus obtained.

[0064] Preparation Examples 2-3

[0065] 100 g of alumina support was loaded with 10 g of Ni and dried at 120 °C for 12 hours, followed by calcination at 550 °C for 5 hours. The resulting sample was then reduced at 480 °C for 6 hours at a hydrogen hourly space velocity (HHSV) of 300 h⁻¹. -1 The desired dehydrogenation catalyst H3 is thus obtained.

[0066] Preparation Examples 2-4

[0067] 100 g of alumina support was loaded with 15 g of Ni and dried at 120 °C for 12 hours, followed by calcination at 550 °C for 5 hours. The resulting sample was then reduced at 500 °C for 6 hours at a hydrogen hourly space velocity (HHSV) of 300 h⁻¹. -1 The desired dehydrogenation catalyst H4 is thus obtained.

[0068] Example 1

[0069] (1) Take 10 g of the above solid acid catalyst G1 and carry out the alkylation reaction of cyclohexylbenzene and cyclohexene in a fixed-bed reactor. The mass space velocity of cyclohexene is 0.5 h⁻¹. -1 The molar ratio of cyclohexylbenzene to cyclohexene was 4. The reaction temperature was 160℃, the reaction pressure was 2.0 MPa, and the reaction time was 1000 hours. The reaction mixture was collected, and the alkylation reaction results are shown in Table 1.

[0070] (2) Take 100 grams of the mixture obtained in step (1) and put it into a vacuum distillation apparatus. Reduce the system pressure to 3 kPa and raise the temperature of the column bottom to 245°C. Distill off the C6 and C12 components in the remaining mixture. The composition of the column bottom components obtained by distillation is shown in Table 2.

[0071] (3) The dehydrogenation reaction of the dehydrogenation catalyst H1 and the dicyclohexylbenzene obtained in the reactor of step (2) was carried out in a fixed-bed reactor. The catalyst loading was 10 g, and the reaction conditions were: the mass hourly space velocity of dicyclohexylbenzene was 1.0 h⁻¹. -1 The reaction temperature was 350℃, the molar ratio of hydrogen to dicyclohexylbenzene was 1.5, the reaction pressure was 1.0MPa, and the reaction time was 1000 hours. The collected reaction mixture was the hydrogenated terphenyl type high-temperature heat transfer oil S1. The dehydrogenation reaction results are shown in Table 3.

[0072] According to the relevant requirements for L-QD340 in the national standard GB 23971, the product specifications of the obtained high-temperature heat transfer oil are shown in Table 4.

[0073] Examples 2-7

[0074] The method is the same as in Example 1, except that the solid catalysts are G2-G7 respectively.

[0075] The alkylation reaction results are shown in Table 1, and the composition of the distillation column bottoms is shown in Table 2.

[0076] Example 8

[0077] The method is the same as in Example 1, except that the hydrogenation catalyst is H2, the obtained high-temperature heat transfer oil is S8, and the composition of the hydrogenation reaction products is shown in Table 3.

[0078] Example 9

[0079] The method is the same as in Example 1, except that the hydrogenation catalyst is H3, the obtained high-temperature heat transfer oil is S9, and the composition of the hydrogenation reaction products is shown in Table 3.

[0080] Example 10

[0081] The method is the same as in Example 1, except that the hydrogenation catalyst is H4, the resulting high-temperature heat transfer oil is S10, and the composition of the hydrogenation reaction products is shown in Table 3.

[0082] Example 11

[0083] The method is the same as in Example 1, except that the alkylation reaction conditions in step (1) are a cyclohexene mass hourly space velocity of 0.8 h⁻¹. -1 The molar ratio of cyclohexylbenzene to cyclohexene was 5. The reaction temperature was 210℃, the reaction pressure was 2.5 MPa, and the reaction time was 1000 hours. The reaction mixture was collected, and the alkylation reaction results are shown in Table 1.

[0084] Example 12

[0085] The method is the same as in Example 1, except that in step (2), the reduced pressure distillation conditions are that the system pressure is reduced to 8 kPa and the temperature of the distillation vessel is increased to 275°C.

[0086] Example 13

[0087] The method is the same as in Example 1, except that the dehydrogenation reaction conditions in step (3) are a mass hourly space velocity (HHSV) of 1.0 h⁻¹ for dicyclohexylbenzene. -1 The reaction temperature was 345℃, the molar ratio of hydrogen to dicyclohexylbenzene was 1.0, the reaction pressure was 0.8MPa, and the reaction time was 1000 hours.

[0088] Table 1. Results of the alkylation reaction of cyclohexylbenzene with cyclohexene (wt%)

[0089] serial number Cyclohexene conversion rate Dicyclohexylbenzene selective Example 1 96.3 96.2 Example 2 92.3 95.2 Example 3 87.0 93.7 Example 4 80.3 92.2 Example 5 88.3 85.5 Example 6 90.2 91.2 Example 7 85.3 87.8 Example 11 94.3 90.0

[0090] Table 2. Composition of the retort (wt%)

[0091]

[0092]

[0093] Table 3. Results of the dehydrogenation reaction of dicyclohexylbenzene (wt%)

[0094]

[0095] Table 4. Various test indicators of the product obtained by this invention

[0096]

[0097]

[0098] As can be seen from the results in Table 4, the hydrogenated terphenyl high-temperature heat transfer oil of the present invention has a low pour point, low requirements for ambient temperature, and a wide range of applications. In addition, the product has good thermal stability, low deterioration rate, and long expected service life. After heating at 340°C for 1000 hours, the deterioration rate is only 3.8%.

[0099] The hydrogenated terphenyl high-temperature heat transfer oil of the present invention has low energy consumption and high yield of hydrogenated terphenyl, and has good application prospects.

[0100] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A hydrogenated terphenyl-based high-temperature heat transfer oil, comprising: dicyclohexylbenzene, cyclohexylbiphenyl, and terphenyl, wherein the content of dicyclohexylbenzene is 10-40% by weight, the content of cyclohexylbiphenyl is 45-55% by weight, and the content of terphenyl is 5-20% by weight; The hydrogenated terphenyl-type high-temperature heat transfer oil is prepared by the following method: (1) Cyclohexylbenzene is reacted with cyclohexene and / or cyclohexanol by alkylation under the action of a solid acid catalyst to generate a mixture containing dicyclohexylbenzene; (2) Remove the C6-C12 components from the mixture containing dicyclohexylbenzene to obtain dicyclohexylbenzene; (3) Partial dehydrogenation of dicyclohexylbenzene under the action of a dehydrogenation catalyst yields hydrogenated terphenyl-type high-temperature heat transfer oil; The conditions for the partial dehydrogenation include: The reaction temperature was 300-450℃, the molar ratio of hydrogen to dicyclohexylbenzene was 0.1-30, and the mass hourly space velocity (HHSV) of dicyclohexylbenzene was 0.1-2.0 h⁻¹. -1 The reaction pressure is 0.5-1.5 MPa.

2. The heat transfer oil according to claim 1, wherein, The total amount of dicyclohexylbenzene, cyclohexylbiphenyl and terphenyl is not less than 70% by weight.

3. The heat transfer oil according to claim 2, wherein, The total amount of dicyclohexylbenzene, cyclohexylbiphenyl and terphenyl is not less than 80% by weight.

4. A method for preparing the hydrogenated terphenyl-type high-temperature heat transfer oil according to any one of claims 1-3, the method comprising the following steps: (1) Cyclohexylbenzene is reacted with cyclohexene and / or cyclohexanol by alkylation under the action of a solid acid catalyst to generate a mixture containing dicyclohexylbenzene; (2) Remove the C6-C12 components from the mixture containing dicyclohexylbenzene to obtain dicyclohexylbenzene; (3) Partial dehydrogenation of dicyclohexylbenzene under the action of a dehydrogenation catalyst yields hydrogenated terphenyl-type high-temperature heat transfer oil; The conditions for the partial dehydrogenation include: a reaction temperature of 300-450℃, a molar ratio of hydrogen to dicyclohexylbenzene of 0.1-30, and a mass hourly space velocity (HHSV) of 0.1-2.0 h⁻¹. -1 The reaction pressure is 0.5-1.5 MPa.

5. The preparation method according to claim 4, wherein, The solid acid catalyst comprises mesoporous molecular sieves and / or heteropoly acids, as well as a binder.

6. The preparation method according to claim 5, wherein, The mesoporous molecular sieve is selected from at least one of mesoporous MWW-22 molecular sieve, mesoporous Y-type molecular sieve, and mesoporous beta molecular sieve.

7. The preparation method according to claim 6, wherein, The mesoporous molecular sieve is a mesoporous MWW-22 molecular sieve and / or a mesoporous Y-type molecular sieve.

8. The preparation method according to claim 5, wherein, The heteropolyacid is phosphomolybdic acid and / or phosphotungstic acid.

9. The preparation method according to claim 8, wherein, The heteropolyacid is phosphotungstic acid.

10. The preparation method according to claim 5, wherein, The binder is selected from at least one of alumina, silica, clay and diatomaceous earth.

11. The preparation method according to claim 10, wherein, The adhesive is aluminum oxide.

12. The preparation method according to claim 5, wherein, Based on the total amount of the solid acid catalyst, the content of mesoporous molecular sieve and / or heteropoly acid is 50-70% by weight, and the content of binder is 30-50% by weight.

13. The preparation method according to claim 5, wherein, The alkylation reaction conditions include: a reaction temperature of 150-230℃, a reaction pressure of 1.5-3.5 MPa, a molar ratio of cyclohexylbenzene to cyclohexene and / or cyclohexanol of 1-6:1, and a mass hourly space velocity (HHSV) of cyclohexene and / or cyclohexanol of 0.1-2.0 h⁻¹. -1 .

14. The preparation method according to claim 5, wherein, In step (2), the C6-C12 components in the mixture containing dicyclohexylbenzene are removed by vacuum distillation.

15. The preparation method according to claim 14, wherein, The conditions for vacuum distillation include: a temperature of 220-300℃ and a vacuum degree of 2-10 kPa.

16. The preparation method according to claim 5, wherein, The dehydrogenation catalyst includes a support and a dehydrogenation metal.

17. The preparation method according to claim 16, wherein, The carrier is alumina and / or silicon oxide.

18. The preparation method according to claim 16, wherein, The dehydrogenating metal is selected from at least one of Group VIII non-noble metals and / or at least one of noble metals.

19. The preparation method according to claim 18, wherein, The dehydrogenating metal is selected from at least one of Ni, Pt, and Pd.

20. The preparation method according to claim 16, wherein, Based on the total amount of dehydrogenation catalyst, the content of support is 85-99% by weight, and the content of dehydrogenation metal is 1-15% by weight.

21. The preparation method according to claim 5, wherein, The conditions for the partial dehydrogenation include: a reaction temperature of 320-400℃, a molar ratio of hydrogen to dicyclohexylbenzene of 0.5-20, and a mass hourly space velocity (HHSV) of 0.8-1.5 h⁻¹. -1 The reaction pressure is 0.6-1.0 MPa.

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