A catalyst for high-temperature-resistant silicone heat-conducting oil and a preparation method thereof

Abstract

This invention relates to a catalyst and its preparation method for a high-temperature resistant organosilicon heat transfer oil. The catalyst for the high-temperature resistant organosilicon heat transfer oil comprises: a Mn catalyst, a cyano ligand, and a reducing agent; wherein the Mn catalyst is Mn(CO)5Br; and the reducing agent is LiHBEt3. The catalyst and its preparation method for the high-temperature resistant organosilicon heat transfer oil described in this invention provide a low-cost catalytic system that can be used in the hydrosilylation reaction of hydrogen-containing silicone oil to prepare a high-temperature resistant organosilicon heat transfer oil.

Description

Technical Field

[0001] This invention belongs to the field of organic chemistry technology, specifically relating to a catalyst and preparation method for a high-temperature resistant organosilicon heat transfer oil. Background Technology

[0002] High-temperature heat transfer oil (also known as heat transfer oil or heat carrier oil) is a highly efficient heat transfer medium with advantages such as uniform heating, precise temperature control, high heat transfer efficiency, energy saving and environmental protection, and ease of transportation and operation. It is widely used in industrial fields, and demand continues to grow. Based on composition and temperature resistance, it is mainly divided into the following types: oil-based heat transfer oil (150-350℃), synthetic oil-based heat transfer oil (300-400℃), silicone oil-based heat transfer oil (-50 to 300℃ or higher), organic ester-based heat transfer oil (250-350℃), fluorinated oil-based heat transfer oil (can exceed 400℃ but is more expensive and pollutes the environment), and water-based heat transfer oil (usually not exceeding 200℃). In comprehensive comparison, silicone oil-based heat transfer oil has significant advantages in overall performance: its high thermal conductivity and low thermal resistance greatly improve heat transfer efficiency, and its excellent high-temperature resistance and chemical stability ensure long-term stable operation in extreme environments. Meanwhile, the low viscosity and good fluidity of silicone oil-based heat transfer oils allow them to quickly fill heat dissipation channels and optimize heat dissipation. Furthermore, silicone oils are environmentally friendly and recyclable, meeting the requirements of green and sustainable development. With the rapid development of technology, especially in high-end fields such as defense, military, and aerospace, higher demands are being placed on the heat resistance of silicone oil-based heat transfer oils.

[0003] Currently, high-hydrogen silicone oil, as one of the important silicone oil products, has become a best-selling organosilicon product both domestically and internationally. Its siloxane backbone contains highly reactive hydrogen groups, which can react with many active groups, resulting in excellent waterproofing. With my country's economic growth, the domestic hydrogen silicone oil industry continues to grow, leading to a rising demand for high-performance products. Currently, hydrogen silicone oil is mainly sold as a bulk product with relatively low prices. To increase its added value, expand its applications, and boost profits, the highly reactive Si-H bonds in the siloxane backbone are functionalized through hydrosilylation reactions, thereby improving the physicochemical properties of hydrogen silicone oil.

[0004] With the development of hydrosilylation reactions, transition metal-catalyzed hydrosilylation reactions have achieved great success. However, most of the catalysts used are precious metals, such as platinum, palladium, and rhodium, which are relatively expensive. In recent years, inexpensive metal catalysts such as iron, cobalt, nickel, and manganese have made good progress in hydrosilylation reactions. However, for hydrosilylation reactions such as the hydrosilylation of hydrogen-containing silicone oils, inexpensive metal catalysts currently perform poorly, exhibiting problems such as low reactivity and difficulty in achieving the reaction. Therefore, it is necessary to develop inexpensive, highly reactive, and substrate-universal metal catalysts for the hydrosilylation of siloxanes.

[0005] In view of this, the present invention proposes a catalyst and preparation method for high-temperature resistant organosilicon heat transfer oil, which is a method for preparing Mn-catalyzed high-temperature resistant organosilicon heat transfer oil. The Mn is Mn(CO)5Br, which is much cheaper than precious metals and has great development potential in the hydrosilylation reaction of hydrogen-containing silicone oil. Summary of the Invention

[0006] The purpose of this invention is to provide a catalyst for high-temperature resistant organosilicon heat transfer oil. This catalytic system is low in cost and can be used in the hydrosilylation reaction of hydrogen-containing silicone oil to prepare high-temperature resistant organosilicon heat transfer oil.

[0007] To achieve the above objectives, the technical solution adopted is as follows:

[0008] A catalyst for a high-temperature resistant organosilicon heat transfer oil includes: a Mn catalyst, a cyano ligand, and a reducing agent;

[0009] The Mn catalyst is Mn(CO)5Br;

[0010] The reducing agent is LiHBEt3.

[0011] Furthermore, the cyano ligand is any one of L1-L8, as shown below:

[0012]

[0013] Furthermore, the molar ratio of the Mn catalyst, cyano ligand, and reducing agent is 0.2:0.2-0.4:0.8-1.2.

[0014] Furthermore, the molar ratio of the Mn catalyst, cyano ligand, and reducing agent is 0.2:0.2:1.

[0015] Another objective of this invention is to provide a method for preparing a high-temperature resistant organosilicon heat-conducting oil. Using the above-mentioned catalyst, the preparation method is mild and low-cost, and can enable the hydrogen-containing silicone oil to undergo a hydrosilylation reaction with olefins to achieve modification of the hydrogen-containing silicone oil.

[0016] To achieve the above objectives, the technical solution adopted is as follows:

[0017] A method for preparing a high-temperature resistant organosilicon heat-conducting oil is as follows:

[0018] After uniformly mixing hydrogen-containing silicone oil, olefins, the above-mentioned catalyst, and organic solvent, a hydrosilylation reaction is carried out under an inert gas atmosphere to obtain a hydrosilylation product, namely the high-temperature resistant organosilicon heat-conducting oil.

[0019] Furthermore, the molar ratio of the olefin to the Mn catalyst in the catalyst is 10:0.1-0.3;

[0020] The hydrosilylation reaction is carried out at a temperature of 100-120℃ for 40-56 hours.

[0021] Furthermore, the molar ratio of the olefin to the Mn catalyst in the catalyst is 10:0.2;

[0022] The hydrosilylation reaction was carried out at a temperature of 110°C for 48 hours.

[0023] Furthermore, the olefin is any one of styrene, methylstyrene, p-tert-butylstyrene, allylbenzene, and 1-allylbenzene;

[0024] The cyano ligand in the catalyst is L8;

[0025] The organic solvent is toluene.

[0026] Furthermore, the olefin is styrene.

[0027] Another objective of this invention is to provide a high-temperature resistant organosilicon heat-conducting oil, which is prepared using the above-mentioned preparation method and has the advantages of large molecular weight and high boiling point compared to the original oil.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. The technical solution of the present invention uses a catalytic system consisting of Mn(CO)5Br, a cyano ligand, and a reducing agent, which can be purchased directly and cheaply. This catalytic system is cheaper and more readily available than precious metal catalysts such as palladium, platinum, and rhodium.

[0030] 2. The technical solution of this invention uses a Mn catalytic system, and the synthesis steps of the hydrogen silylation reaction of hydrogen-containing silicone oil and olefin are simple. The resulting high-temperature resistant organosilicon heat transfer oil is characterized by NMR, IR, GPC, and TG. Compared with the product before modification, the molecular weight and boiling point are significantly increased, and the product has great application potential.

[0031] 3. The technical solution of this invention adopts a Mn catalytic system, which has the characteristics of mild conditions and high yield. It breaks the traditional characteristics of using precious metals to produce organosilicon products and provides a new experimental idea for realizing the production of cheap and efficient silicone oil products. Attached Figure Description

[0032] Figure 1 The NMR spectrum of product 2c is shown in the left figure, which is the proton NMR spectrum, and the right figure is the carbon NMR spectrum.

[0033] Figure 2 Infrared characterization of products 2a, 2b, and 2c.

[0034] Figure 3 Thermogravimetric characterization of products 2b and 2c.

[0035] Figure 4 The NMR spectrum of the reaction product of p-methylstyrene is shown.

[0036] Figure 5 The NMR of the reaction product of tert-butylstyrene is shown.

[0037] Figure 6 The NMR of the product of the reaction with allylbenzene.

[0038] Figure 7 NMR of the reaction product of 1-allylbenzene. Detailed Implementation

[0039] To further illustrate the catalyst and preparation method of the high-temperature resistant organosilicon heat-conducting oil of the present invention, and to achieve the intended purpose of the invention, the following, in conjunction with preferred embodiments, details the specific implementation, structure, features, and effects of the catalyst and preparation method of the high-temperature resistant organosilicon heat-conducting oil proposed according to the present invention. In the following description, different "an embodiment" or "an embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0040] The catalyst and preparation method of the high-temperature resistant organosilicon heat transfer oil of the present invention will be further described in detail below with reference to specific embodiments:

[0041] This invention discloses a catalyst and preparation method for high-temperature resistant organosilicon heat transfer oil. It is a method for synthesizing high-temperature resistant organosilicon heat transfer oil by hydrosilylation of hydrogen-containing silicone oil using a Mn catalytic system. The method is simple, low-cost, and mild. The decomposition temperature of the obtained high-temperature resistant organosilicon heat transfer oil is around 490℃, and the average molecular weight is 12514 g / mol.

[0042] The technical solution of this invention is as follows:

[0043] A catalyst for a high-temperature resistant organosilicon heat transfer oil includes: a Mn catalyst, a cyano ligand, and a reducing agent;

[0044] The Mn catalyst is Mn(CO)5Br;

[0045] The reducing agent is LiHBEt3.

[0046] Preferably, the cyano ligand is any one of L1-L8, as shown below:

[0047]

[0048] In the above technical solution, any one of the cyano ligands from L1 to L8 is used. This application has experimentally discovered that when no cyano ligand is added, only Mn(CO)5Br and a reducing agent are added, a weak hydrosilylation product can be observed. When a cyano ligand is added, the cyano ligand undergoes ligand exchange with CO, forming a coordination intermediate with Mn, and a significant increase in conversion rate can be observed.

[0049] Preferably, the molar ratio of the Mn catalyst, cyano ligand, and reducing agent is 0.2:0.2-0.4:0.8-1.2.

[0050] More preferably, the molar ratio of the Mn catalyst, cyano ligand, and reducing agent is 0.2:0.2:1.

[0051] In the above technical solution, the amount of cyano ligand used is related to its cyano structure.

[0052] A method for preparing a high-temperature resistant organosilicon heat-conducting oil is as follows:

[0053] After uniformly mixing hydrogen-containing silicone oil, olefins, the above-mentioned catalyst, and organic solvent, a hydrosilylation reaction is carried out under an inert gas atmosphere to obtain a hydrosilylation product, namely the high-temperature resistant organosilicon heat-conducting oil.

[0054] Preferably, the molar ratio of the olefin to the Mn catalyst in the catalyst is 10:0.1-0.3;

[0055] The hydrosilylation reaction is carried out at a temperature of 100-120℃ for 40-56 hours.

[0056] More preferably, the molar ratio of the olefin to the Mn catalyst in the catalyst is 10:0.2;

[0057] The hydrosilylation reaction was carried out at a temperature of 110°C for 48 hours.

[0058] Preferably, the olefin is any one of styrene, methylstyrene, p-tert-butylstyrene, allylbenzene, and 1-allylbenzene;

[0059] The cyano ligand in the catalyst is L8;

[0060] The organic solvent is toluene.

[0061] More preferably, the olefin is styrene.

[0062] A high-temperature resistant organosilicon heat transfer oil, prepared by the above-mentioned method, has the advantages of large molecular weight and high boiling point compared with the original oil.

[0063] The structural formulas of the cyano ligands L1-L8 in the examples are shown below:

[0064]

[0065] The reducing agent used in the examples is LiHBEt3.

[0066] All raw materials used in this invention are commercially available.

[0067] Example 1.

[0068] The reaction formula is shown below:

[0069]

[0070] The specific steps are as follows:

[0071] Under a nitrogen atmosphere, Mn(CO)5Br (2 mol%), cyano ligand (Structural formula L8, 2 mol%), 2a (styrene, 4 mmol), and 2b (hydrogen-containing silicone oil, 0.2 ml) were added to a 25 ml reaction tube, dissolved in toluene, and finally a reducing agent (10 mol%) was added. The mixture was then placed in a magnetic stirrer at 110 °C and reacted for 48 h. After the reaction was complete, methanol was added, and the solvent and low-boiling-point volatile substances were removed by rotary evaporation. Hexane was added, and the mixture was centrifuged. The supernatant was collected, and the solvent was evaporated to obtain the modified high-temperature resistant organosilicon heat-conducting oil (2c).

[0072] In this embodiment, the mol% of Mn catalyst, cyano ligand, and reducing agent refers to the molar percentage relative to styrene.

[0073] The high-temperature resistant organosilicon heat transfer oil (2c) was characterized by nuclear magnetic resonance, and the results are as follows: Figure 1 As shown. By Figure 1 It can be seen that a benzene ring is attached to the synthesized product.

[0074] Example 2.

[0075] GPC test: GPC test was performed on compounds 2b (hydrogen-containing silicone oil) and 2c (high-temperature resistant organosilicon thermal oil) in Example 1. The results are shown in Table 1-2.

[0076] GPC data in Table 1 2b

[0077]

[0078] As shown in Table 1-2, the average molecular weight of the product increased significantly compared to before modification.

[0079] Example 3.

[0080] Infrared analysis: Compounds 2a (styrene), 2b (hydrogen-containing silicone oil), and 2c (high-temperature resistant organosilicon thermal oil) in Example 1 were characterized by infrared spectroscopy.

[0081] The results are as follows Figure 2 As shown. From Figure 2 It can be seen that:

[0082] For sample 2a: at 3000-3100 cm -1 Nearby: Stretching vibration of CH on the benzene ring (3000-3100 cm⁻¹) -1 The range is the characteristic region of the benzene ring (CH). Combining this with the benzene ring in the molecular formula confirms the presence of the benzene ring. (The range is 1600-1500 cm⁻¹). -1 Nearby: Skeletal vibrations of the benzene ring (1600, 1580, 1500 cm⁻¹) -1 The presence of peaks (such as isotopes) further confirmed the structure of the benzene ring. Additionally, if an alkene C=C double bond is present, peaks at 1620-1680 cm⁻¹ will be observed. -1 Weak peaks may appear within this range (requires structural analysis; the double bond in styrene is conjugated with the benzene ring, therefore the peak may broaden or shift). At 700-750 cm⁻¹ -1 and 690cm -1 Nearby: out-of-plane bending vibrations of monosubstituted benzene rings (700-750 cm⁻¹) -1 The broad peak within the range is 690cm. -1 The peak (of the benzene ring) is consistent with the structure of "monosubstituted styrene", indicating that the benzene ring is in a monosubstituted mode.

[0083] For sample 2b: at 2900-3000 cm⁻¹ -1 Nearby: Primarily stretching vibrations of saturated CH groups (if the molecule contains alkyl side chains, such as -CH3, -CH2-). This indicates that the side groups of the siloxane contain saturated alkyl groups (corresponding to alkylsiloxane chains in the structure). At 1400-1470 cm⁻¹ -1 Nearby: CH bending vibrations of alkyl groups (such as symmetric deformation of -CH3 and shear vibration of -CH2-) further confirmed the presence of saturated alkyl groups. At 3000-3100 cm⁻¹ -1 No benzene ring peaks were observed within the range: this is consistent with the "no benzene ring" condition in the structure. The spectrum is clean, highlighting the characteristics of the siloxane and alkyl groups.

[0084] For sample 2c: at 3000-3100cm -1 Nearby: Similar to 2a, stretching vibrations of CH on the benzene ring are present, indicating that the side groups contain a benzene ring. At 2900-3000 cm⁻¹ -1Nearby: There are also CH stretching vibrations of saturated alkyl groups (the -CH2- and -CH3 moieties in the phenethyl side group). Therefore, the peaks in this region are more complex (CH vibrations of the benzene ring and alkyl groups overlap). (1600-1500 cm⁻¹) -1 Nearby: Skeletal vibration peaks of the benzene ring (same as 2a). However, since the benzene ring is linked to the siloxane via an alkyl chain (-CH2-CH2-), the peak shape may be sharper (the conjugation effect is weaker than in 2a when the double bonds are directly connected). At 700-750 cm⁻¹ -1 and 690cm -1 Nearby: out-of-plane bending vibrations of the monosubstituted benzene ring (same as 2a). However, the peak intensity may be slightly weaker or shifted due to the separation of the alkyl chain, and the addition follows the anti-Markovnikov structure.

[0085] Example 4.

[0086] Thermogravimetric analysis: thermogravimetric characterization of products 2b and 2c.

[0087] Result: From Figure 3 It can be seen that the curve of 2b fluctuated during the heating process, which should be due to the sample cracking during the heating process. The total weight loss of 2c was 42.0%, and the whole process can be divided into two stages. Stage 1: From room temperature to 500℃, the sample lost 22.4% of its weight, and the maximum rate of mass loss (DTG) occurred at 261.2℃. Stage 2: From 500℃ to 800℃, the weight loss rate changed. In this temperature range, the sample lost approximately 19.6% of its weight, and the maximum rate of mass loss (DTG) occurred at 493.9℃. The weight loss temperature of the first stage is presumably the thermal decomposition temperature of the coupling products of the hydrogen-containing silicone oil itself, and the weight loss temperature of the second stage is presumably the thermal decomposition temperature of the modified silicone oil.

[0088] Example 5.

[0089] The operating steps of Example 5 are the same as those of Example 1, except for the selection of solvent, temperature, catalyst, and additives. See Table 3 for details.

[0090] Table 3 Condition Optimization

[0091]

[0092] Note: np in Table 3 indicates that no target product was generated.

[0093] As shown in Table 3, under conditions where there is no reducing agent, or the reducing agent is not LiHBEt3, or only a manganese catalyst is used, or the reaction solvent is not toluene, it is impossible to synthesize organosilicon thermal conductive oil using hydrogen-containing silicone oil and olefins. Therefore, based on the proposed new catalyst (Mn catalyst, cyano ligand, reducing agent), this invention realizes a new synthesis method for organosilicon thermal conductive oil, which can use hydrogen-containing silicone oil and olefins as reactants.

[0094] Furthermore, when no ligand is added, only Mn(CO)5Br and activator are added, weak hydrosilylation products can be observed. When a cyano ligand is added, the cyano ligand exchanges with CO and forms a coordination intermediate with Mn, and a significant increase in conversion rate can be observed.

[0095] Example 6.

[0096] The operating steps of Example 6 are the same as those of Example 1, except for the selection and dosage of the cyano ligand. The ligand effects are compared in Table 4.

[0097] Table 4 Ligand Screening

[0098]

[0099]

[0100] Table 4 shows that by comparing the proportions of Si-H peaks and aromatic peaks in the products generated under each condition using 1H NMR characterization, the extent of the reaction was determined. It was found that the reaction yielded the best results when L8 was selected as the cyano ligand. Furthermore, NMR characterization showed that the NMR data of the products using L1-L8 as cyano ligands were consistent with those of 2c, indicating that all of these methods could be used for the synthesis of organosilicon thermal conductive oils.

[0101] Example 7.

[0102] The operation steps of Example 7 are the same as those of Example 1, except that the amount of each component in the catalyst and the amount of olefin are as shown in Table 5.

[0103] Table 5

[0104]

[0105] Example 8.

[0106] The operation steps of Example 8 are the same as those of Example 1, except for the reaction temperature and time, as detailed in Table 6.

[0107] Table 6

[0108]

[0109] Example 9.

[0110] Reactions of other substrates: The specific operating procedures are the same as in Example 1, except for the choice of the substrate alkene. The specific reaction formulas are shown below:

[0111] (1) The olefin is: 4-methylstyrene

[0112]

[0113] NMR data: such as Figure 4 As shown.

[0114] (2) The olefin is: p-tert-butylstyrene

[0115]

[0116] NMR data: such as Figure 5 As shown.

[0117] (3) The olefin is: allylbenzene

[0118]

[0119] NMR data: such as Figure 6 As shown.

[0120] (4) The olefin is: 1-enebutene

[0121]

[0122] NMR data: such as Figure 7 As shown.

[0123] Depend on Figure 4-7 As shown, all synthesized products were linked to a benzene ring, meaning that the target product was generated. Furthermore, this example included reactions of other substrates, and their properties and characterization were similar to those in Example 1.

[0124] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A catalyst for high-temperature-resistant silicone heat-conducting oil, characterized by comprising a metal oxide and a metal salt. include: Mn catalyst, cyano ligand, reducing agent; The Mn catalyst is Mn(CO)5Br; The reducing agent is LiHBEt3; The cyano ligand is any one of L1-L8, as shown below: 。 2. The catalyst according to claim 1, characterized in that, The molar ratio of the Mn catalyst, cyano ligand, and reducing agent is 0.2: 0.2-0.4: 0.8-1.

2.

3. The catalyst according to claim 2, characterized in that, The molar ratio of the Mn catalyst, cyano ligand, and reducing agent is 0.2:0.2:

1.

4. A method for preparing a high-temperature resistant organosilicon heat-conducting oil, characterized in that, The preparation method is as follows: After uniformly mixing hydrogen-containing silicone oil, olefin, catalyst as described in any one of claims 1-3, and organic solvent, a hydrosilylation reaction is carried out under an inert gas atmosphere to obtain a hydrosilylation product, namely the high-temperature resistant organosilicon heat-conducting oil.

5. The preparation method according to claim 4, characterized in that, The molar ratio of the olefin to the Mn catalyst in the catalyst is 10:0.1-0.3; The hydrosilylation reaction is carried out at a temperature of 100-120 °C for a time of 40-56 h.

6. The preparation method according to claim 5, characterized in that, The molar ratio of the olefin to the Mn catalyst in the catalyst is 10:0.2; The hydrosilylation reaction was carried out at a temperature of 110 °C for 48 h.

7. The preparation method according to claim 4, characterized in that, The olefin is any one of styrene, methylstyrene, p-tert-butylstyrene, allylbenzene, and 1-allylbenzene; The cyano ligand in the catalyst is L8; The organic solvent is toluene.

8. The preparation method according to claim 7, characterized in that, The olefin mentioned is styrene.

9. A high-temperature resistant organosilicon thermal oil, characterized in that, It is prepared by the preparation method according to any one of claims 4-8.

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