Method for synthesizing diphenylmethane compounds and benzophenone compounds by zeolite-catalyzed diphenylmethanol compounds

Abstract

The invention discloses a method for simultaneously synthesizing diphenylmethane compounds and benzophenone compounds by catalyzing diphenylmethanol compounds through zeolite, and belongs to the technical field of organic synthetic chemistry. The invention uses an acidic zeolite molecular sieve as a catalyst, does not need to add any solvent, and uses diphenylmethanol as a raw material to undergo a disproportionation reaction in a nitrogen or air atmosphere to complete the synthesis of benzophenone and diphenylmethane. The invention prepares benzophenone and diphenylmethane simultaneously by disproportionating diphenylmethanol. The reaction conditions are mild and the process route is simple, and the invention is an efficient synthesis method.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthetic chemistry, and particularly relates to a method for synthesizing benzophenone and diphenylmethane by using benzhydrol as catalyst by zeolite molecular sieve. Background Art

[0002] Benzophenone and diphenylmethane are used as important intermediate raw materials and are widely used in various industries such as the fragrance industry, dye industry and drug synthesis. Among them, diphenylmethane is also used as a synergist for pesticides and insecticides. Adding it to saturated linear polyester can improve its thermal stability, and adding it to jet fuel can improve its stability and lubrication performance. It is a very important fine chemical. Benzophenone can also be used in the film manufacturing industry, photosensitizers for film coatings, styrene polymerization inhibitors, photoinitiators, ultraviolet curing agents and additives, etc., and is also a very important fine chemical.

[0003] Currently, the disproportionation reaction of benzhydrol is one of the methods for preparing diphenylmethane and benzophenone at the same time. However, most reactions require harsh conditions. For example, direct reduction of alcohol in supercritical water to synthesize benzophenone and diphenylmethane requires high temperature and high pressure to achieve the reaction, which makes it difficult to achieve industrial production (J.Supflu., 2014.11.017, J.Supflu., 2013.02.012); in an alkaline environment, Rh / C is used as a catalyst to disproportionate benzhydrol into diphenylmethane and benzophenone. In this method, In this method, precious metal catalysts such as Pd / C, Pt / C, Ru / C, and Rh / C are required, which are expensive and not suitable for industrial production (Green Chem., 2014, 16, 3439); CuOY catalyzes diphenylmethane to produce diphenylmethane and benzophenone. In this method, the synergistic effect of Y zeolite and transition metal CuO is required (J. Nanomater, 2008, 2008.), which is a free radical reaction and requires high temperature reaction conditions; when Y zeolite is used alone as a catalyst, only a single product of diphenylmethane can be obtained.

[0004] Thus, the above-mentioned methods have the disadvantages of high temperature, high pressure, high cost, low yield, and inability to be industrialized, etc. Therefore, from the perspective of sustainable green synthesis, it is very important to develop a simple, safe, economical, and efficient synthesis method.

[0005] In the present invention, H-Beta zeolite molecular sieve is used as a catalyst, and under mild reaction conditions, no additional solvent is needed to synthesize diphenylmethane and benzophenone using diphenylmethanol as a raw material. Summary of the invention

[0006] Using acidic zeolite molecular sieve as catalyst, in nitrogen or air atmosphere, without adding any solvent, the synthesis of benzophenone and diphenylmethane is achieved using diphenylmethanol as raw material.

[0007] The characteristics of the present invention are as follows: ① There is no literature report on the method of synthesizing benzophenone and diphenylmethane by using diphenylmethanol as a raw material under the action of an acidic zeolite catalyst, and this is the first report; ② No additional chemical reagents need to be added as solvents, and the waste liquid generated during industrial amplification is also greatly reduced, making the entire process more green and environmentally friendly; ③ The product yield is good, and basically no by-product generation can be achieved.

[0008] The technical solution of the present invention is as follows:

[0009] Benzhydrol is used as a reaction raw material, a set amount of acidic zeolite molecular sieve is added into a reaction tube as a catalyst, and the mixture is reacted at a set reaction temperature under a nitrogen or air atmosphere to obtain a mixed product containing benzophenone and diphenylmethane, and then the product is dissolved in ethyl acetate, and the obtained liquid product is separated by column chromatography after centrifugation and rotary evaporation to separate benzophenone and diphenylmethane.

[0010]

[0011] R1 is selected from H, F, Cl, Br, OMe, Me, NO2 or CF3; R2 is selected from H, Cl or OMe. R1 and R2 are substituents at the ortho, meta or para positions.

[0012] The amount of compound 1 added in the reaction is 1:50 to 1:200 (mol / g) relative to the amount of the catalyst.

[0013] The reaction temperature is 60-140°C and the reaction time is 1-12 hours. The more preferred reaction temperature is 80-140°C.

[0014] Furthermore, the catalyst is H-Beta zeolite molecular sieve, and the silicon-aluminum ratio of H-Beta is 14-20.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The present invention does not require the addition of additional chemical reagents as solvents, does not require high temperature and high pressure conditions, and provides a simple, clean and green reaction path.

[0017] (2) The present invention uses industrially mature H-Beta zeolite molecular sieve to catalyze the reaction. H-Beta zeolite molecular sieve has very good thermal stability and hydrothermal stability, so that the catalyst can be recycled and reused many times after the reaction. Compared with conventional homogeneous catalysis, it further reduces production costs and environmental pollution, and is conducive to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the target product of Example 1, diphenylmethane 1 H-NMR spectrum.

[0019] Figure 2 It is the target product benzophenone of Example 1 1 H-NMR spectrum.

[0020] Figure 3 The target product of Example 2, 4,4'-difluorodiphenylmethane 1 H-NMR spectrum.

[0021] Figure 4 The target product of Example 2, 4,4'-difluorobenzophenone 1 H-NMR spectrum.

[0022] Figure 5 The target product of Example 3, 4,4'-dimethoxydiphenylmethane 1 H-NMR spectrum.

[0023] Figure 6 The target product of Example 3, 4,4'-dimethoxybenzophenone 1 H-NMR spectrum.

[0024] Figure 7 The target product of Example 4, 4-chlorodiphenylmethane 1 H-NMR spectrum.

[0025] Figure 8 The target product 4-chlorobenzophenone of Example 4 1 H-NMR spectrum.

[0026] Fig. 9 It is the target product 4-methyldiphenylmethane of Example 5 1 H-NMR spectrum.

[0027] Fig.10 The target product of Example 5, 4-methylbenzophenone 1 H-NMR spectrum. DETAILED DESCRIPTION

[0028] In order to further understand the purpose, content and advantages of the present invention, the specific embodiments of the present invention are described in detail below, but they are not limited to the following examples, and the reaction conditions should be changed according to the actual situation. Unless otherwise specified, the reagents and instruments used in the following examples are commercially available products.

[0029] Embodiment 1:

[0030]

[0031] 30 mg HBeta catalyst (commercially available) and 0.3 mmol benzhydrol were added to the reaction tube, and the mixture was reacted in a 120°C heater under a nitrogen atmosphere for 2 h. After cooling to room temperature, ethyl acetate was added to the reaction solution, and the sample was centrifuged. The conversion rate and selectivity were determined by GC. The final calculated yield of diphenylmethane was 50%, and the yield of benzophenone was 50%. The reaction solution was rotary evaporated and separated by column chromatography (eluting reagent was a mixture of petroleum ether and ethyl acetate) to obtain the product.

[0032] Embodiment 2:

[0033]

[0034] 30 mg HBeta catalyst and 0.3 mmol 4,4'-difluorobenzhydrol were added to the reaction tube, and the mixture was reacted in a 120°C heater for 2 h under a nitrogen atmosphere. After cooling to room temperature, ethyl acetate was added to the reaction solution, and the sample was centrifuged. The conversion rate and selectivity were determined by GC. The final calculation showed that the yield of 4,4'-difluorodiphenylmethane was 50%, and the yield of 4,4'-difluorobenzophenone was 50%. The reaction solution was rotary evaporated and separated by column chromatography (eluting reagent was a mixture of petroleum ether and ethyl acetate) to obtain the product. The characterization data of the product are as follows:

[0035] bis(4-fluorophenyl)methane:colorlessliquid 1 HNMR (400MHz, Chloroform-d) δ7.00 (dd, J=8.4, 5.5Hz, 4H), 6.86 (dd, J=9.8, 7.5Hz, 4H), 3.80 (s, 2H).

[0036] bis(4-fluorophenyl)methanone:whitesolid 1 HNMR(400MHz,Chloroform-d)δ7.76–7.67(m,4H),7.11–7.02(m,4H).

[0037] Embodiment 3:

[0038]

[0039] 30 mg HBeta catalyst and 0.3 mmol dimethoxybenzhydrol were added to the reaction tube, and the mixture was reacted in a 120°C heater under a nitrogen atmosphere for 2 h. After cooling to room temperature, ethyl acetate was added to the reaction solution, and the sample was centrifuged. The conversion rate and selectivity were determined by GC. The final calculation showed that the yield of 4,4'-dimethoxydiphenylmethane was 50%, and the yield of 4,4'-dimethoxybenzophenone was 50%. The reaction solution was rotary evaporated and separated by column chromatography (eluting reagent was a mixture of petroleum ether and ethyl acetate) to obtain the product. The characterization data of the product are as follows:

[0040] bis(4-methoxyphenyl)methane:colorlessliquid 1 HNMR(300MHz,Chloroform-d)δ6.98(d,J=8.7Hz,4H),6.72(d,J=8.6Hz,4H),3.75(s,2H),3.65(s,6H).

[0041] bis(4-methoxyphenyl)methanone:lightyellowsolid 1 HNMR(300MHz,Chloroform-d)δ7.75–7.66(dt,4H),6.90–6.85(dt,4H),3.79(s,6H).

[0042] Embodiment 4:

[0043]

[0044] 30 mg HBeta catalyst and 0.3 mmol 4-chlorobenzhydrol were added to the reaction tube, and the mixture was reacted in a 120°C heater under a nitrogen atmosphere for 2 h. After cooling to room temperature, ethyl acetate was added to the reaction solution, and the sample was centrifuged. The conversion rate and selectivity were determined by GC. The final calculation showed that the yield of 4-chlorodiphenylmethane was 50%, and the yield of 4-chlorobenzophenone was 50%. The reaction solution was rotary evaporated and separated by column chromatography (eluting reagent was a mixture of petroleum ether and ethyl acetate) to obtain the product. The characterization data of the product are as follows:

[0045] 1-benzyl-4-chlorobenzene:colorlessoilliquid 1 HNMR(300MHz,Chloroform-d)δ7.23–7.08(m,5H),7.05(d,J=6.7Hz,3H),7.00(d,J=8.4Hz,3H),3.83(s,2H).

[0046] (4-Chlorophenyl)phenyl-methanone:whitesolid 1 HNMR(300MHz,Chloroform-d)δ7.72–7.60(m,4H),7.49(t,J=7.4Hz,1H),7.43–7.30(m,4H).

[0047] Embodiment 5:

[0048]

[0049] 30 mg HBeta catalyst and 0.3 mmol 4-methylbenzhydrol were added to the reaction tube, and the mixture was reacted in a 120°C heater under a nitrogen atmosphere for 2 h. After cooling to room temperature, ethyl acetate was added to the reaction solution, and then centrifuged, separated, and sampled. The conversion rate and selectivity were determined using GC. The final calculated yield of 4-methyldiphenylmethane was 52%, and the yield of 4-methylbenzophenone was 48%. The reaction solution was rotary evaporated and separated by column chromatography (eluting reagent was a mixture of petroleum ether and ethyl acetate) to obtain the product. The characterization data of the product are as follows:

[0050] 1-benzyl-4-methylbenzene:colorlessoilliquid 1 HNMR(400MHz,Chloroform-d)δ7.21–7.12(m,2H),7.11–7.03(m,3H),6.98(s,4H),3.83(s,2H),2.21(s,3H).

[0051] phenyl(p-tolyl)methanone:whitesolid 1 HNMR(400MHz,Chloroform-d)δ7.79(dd,J=8.3,1.4Hz,2H),7.73(d,J=8.2Hz,2H),7.60–7.55(m,1H),7.47(t,J=7.5Hz,2H),7.31–7.26(m,2H),2.44(s,3H).

[0052] Embodiment 6:

[0053] 30 mg of Beta catalyst and 0.3 mmol of benzhydrol were added to the reaction tube, and the reaction was carried out in a 120°C heater under a nitrogen atmosphere for 2 h. After cooling to room temperature, ethyl acetate was added to the reaction solution, which was then centrifuged, separated, and sampled. The conversion rate and selectivity were determined using GC, and the final calculated yields of diphenylmethane and benzophenone were 36% and 36%.

[0054] The reaction time of Example 6 was extended to 12 h, and other conditions remained unchanged. The conversion rate and selectivity were determined by GC. The final calculated yields of diphenylmethane and benzophenone were 48.3% and 48.3%.

[0055] Embodiment 7:

[0056] 30 mg of HBeta catalyst (commercially available) and 0.3 mmol of benzhydrol were added to the reaction tube, and the mixture was reacted in a 30°C heater under a nitrogen atmosphere for 12 h. After cooling to room temperature, ethyl acetate was added and the mixture was sampled by centrifugation. The conversion rate and selectivity were determined by GC, and no target product was generated.

[0057] The reaction time of Example 7 was extended to 60 h, and other conditions remained unchanged. The conversion rate and selectivity were determined by GC. The final calculated yields of diphenylmethane and benzophenone were 0.8% and 0.8%.

[0058] Embodiment 8:

[0059] 30 mg HBeta catalyst (commercially available) and 0.3 mmol benzhydrol were added to the reaction tube, and the mixture was reacted in a 60°C heater under a nitrogen atmosphere for 12 h. After cooling to room temperature, ethyl acetate was added and the mixture was centrifuged for sampling. The conversion rate and selectivity were determined by GC. The final calculated yields of diphenylmethane and benzophenone were 2.5% and 2.5%, respectively. The reaction solution was rotary evaporated and separated by column chromatography (eluting reagent was a mixture of petroleum ether and ethyl acetate) to obtain the product.

[0060] The reaction time of Example 7 was extended to 24 h, and other conditions remained unchanged. The conversion rate and selectivity were determined by GC. The final calculated yields of diphenylmethane and benzophenone were 3.7% and 3.7%.

[0061] Comparative Example 1:

[0062] The preparation method of HBeta zeolite molecular sieve treated with 1.0M nitric acid is as follows: prepare a 1.0mol / L nitric acid aqueous solution, add it to a water bath bottle according to m(Beta) : m(HNO3) = 1:20, mix well, and treat it in a water bath at 80℃ for 4h; after cooling to room temperature, wash it to neutrality (pH = 7); add it to a beaker according to m(Beta) : m(HNO3) = 1:10, adjust the pH to 3 with 0.1mol / L nitric acid aqueous solution, stir it stably for 3h, filter it, dry it, and calcine it at 550℃ for 4h; repeat the above exchange process twice, and the product obtained is the acidic zeolite 1.0M nitric acid treated HBeta, recorded as HBeta-1. The framework silicon-aluminum ratio of HBeta-1 zeolite is 70.

[0063] 30 mg of HBeta-1 catalyst and 0.3 mmol of benzhydrol were added to the reaction tube, and the mixture was reacted in a 120°C heater under a nitrogen atmosphere for 2 h. After the mixture cooled to room temperature, ethyl acetate was added to the reaction solution, which was then centrifuged, separated, and sampled. The conversion rate and selectivity were determined using GC, and the final calculated yields of diphenylmethane and benzophenone were 3%, and 3%, respectively.

[0064] Comparative Example 2:

[0065] 30 mg of USY catalyst and 0.3 mmol of benzhydrol were added to the reaction tube, and the reaction was carried out in a 120°C heater under a nitrogen atmosphere for 2 h. After cooling to room temperature, ethyl acetate was added to the reaction solution, which was then centrifuged, separated, and sampled. The conversion rate and selectivity were determined using GC, and the final calculated yields of diphenylmethane and benzophenone were 8.5% and 8.7%.

[0066] Comparative Example 3:

[0067] 30 mg of H-ZSM-5 catalyst and 0.3 mmol of benzhydrol were added to the reaction tube, and the mixture was reacted in a 120° C. heater under a nitrogen atmosphere for 2 h. After cooling to room temperature, ethyl acetate was added to the reaction solution, which was then centrifuged and sampled. The conversion rate and selectivity were determined by GC, and the final calculated yields of diphenylmethane and benzophenone were 12.2% and 13.5%.

[0068] Compared with Example 1, the difference is that the reaction conditions are the same, and the details of the selection of the reaction substrate are shown in Table 1.

[0069] Table 1 Reaction range of substrates

[0070]

[0071]

[0072] Table 2 Substrate activity and target product selectivity under different reaction conditions

[0073]

Claims

1. A method for synthesizing diphenylmethane compounds and benzophenone compounds by using benzhydrol compounds catalyzed by zeolite, characterized in that: Using an acidic zeolite molecular sieve as a catalyst and a benzhydrol compound 1 as a raw material, a heating reaction is carried out at a reaction temperature of 60 to 140 °C to obtain diphenylmethane compounds and benzophenone compounds; ； R1 is selected from H, F, Cl, Br, OMe, Me, NO2 or CF3; R2 is selected from H, Cl or OMe; the acidic zeolite molecular sieve is H-Beta zeolite molecular sieve.

2. The method for synthesizing diphenylmethane compounds and benzophenone compounds by using zeolite-catalyzed benzhydrol compounds according to claim 1, characterized in that: R1 and R2 are substituents at the ortho, meta or para positions.

3. The method for synthesizing diphenylmethane compounds and benzophenone compounds by using zeolite-catalyzed benzhydrol compounds according to claim 1, characterized in that: The amount of compound 1 added in the reaction is 1:50~1:200 (mol / g) relative to the amount of the catalyst.

4. The method for synthesizing diphenylmethane compounds and benzophenone compounds by using benzhydrol compounds catalyzed by zeolite according to claim 1, characterized in that: No solvent needs to be added during the reaction.

5. The method for synthesizing diphenylmethane compounds and benzophenone compounds by using benzhydrol compounds catalyzed by zeolite according to claim 1, characterized in that: The reaction temperature is 80-140 °C, and the reaction time is 1-12 h.

6. The method for synthesizing diphenylmethane compounds and benzophenone compounds by using benzhydrol compounds catalyzed by zeolite according to claim 1, characterized in that: After the reaction product is cooled to room temperature, a solvent is added to dissolve it, and after centrifugation and rotary evaporation, the obtained liquid product is separated by column chromatography to obtain benzophenone and diphenylmethane respectively.

Images