A method for the joint preparation of styrene oxide and benzaldehyde by heterogeneous catalytic epoxidation of styrene
A technology for epoxidizing styrene and styrene oxide, which is applied in the fields of oxidative preparation of carbonyl compounds, chemical recovery, organic chemistry, etc. It can solve the problems of unavoidable traces of organic chlorine, low conversion rate of toluene in one pass, and difficult control of reaction temperature and other problems, to achieve the effect of easy separation, obvious solvent effect and convenient operation
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Embodiment 1-5
[0023] Examples 1-5: SiO with different n(Si / Ti) 2 -TiO 2 Combined Preparation of Styrene Oxide and Benzaldehyde by Composite Airgel Catalyzed Epoxidation of Styrene
[0024]Into five 50 mL two-necked round bottom flasks, add 0.25 g of catalysts with n(Si / Ti) of 5, 7, 9, 20, and 40 prepared above, 1.04 g (10 mmol) of styrene, N,N- With 10 g of dimethylformamide, the flask was reacted at a constant temperature in an oil bath at 60°C and refluxed for 6 h while stirring continuously. 10 ml (10 mmol) of 30% hydrogen peroxide was added at a constant speed by a micro-sampling pump, and the dropping time was 0.5 h. After the reaction, the catalyst was separated by filtration, and the filtrate was analyzed by gas chromatography. The filtrate was rectified, and the fractions at 180°C and 190°C were taken respectively to obtain styrene oxide and benzaldehyde in sequence. The product was qualitatively analyzed by GC-MS (CP-3800 / Saturn2000 gas / mass spectrometer, capillary column: CP-SI...
Embodiment example 6~9
[0028] Implementation Cases 6~9: SiO with Different Catalyst Consumption 2 -TiO 2 Combined Preparation of Styrene Oxide and Benzaldehyde by Composite Airgel Catalytic Epoxidation of Styrene
[0029] Choose SiO with n(Si / Ti) = 9 2 -TiO 2 Composite airgel was used as catalyst, and 0.15 g, 0.25 g, 0.35 g and 0.45 g were weighed respectively (the mass ratios of substrate styrene and catalyst were 6.7:1, 4:1, 2.9:1, 2.2:1) and released into four 50mL two-necked flasks, and other operating conditions were the same as in Examples 1 to 5. The reaction results are shown in Table 2.
[0030] Table 2 Effect of different catalyst dosage on epoxidation reaction
[0031]
[0032] As can be seen from Table 2, the catalyst dosage increases, the styrene conversion rate improves, the styrene oxide selectivity and the benzaldehyde selectivity all improve, but when the catalyst dosage exceeds 0.35 g, the styrene conversion rate, epoxybenzene Ethane selectivity and benzaldehyde selectivit...
Embodiment example 10~12
[0033] Implementation Cases 10~12: Different n(H 2 o 2 / styrene) under the epoxidation of styrene to jointly prepare the result of styrene oxide and benzaldehyde
[0034] Choose SiO with n(Si / Ti) = 9 2 -TiO 2 Composite aerogels were used as catalysts, and n(H 2 o 2 / styrene) is 0.5, 1 and 2 30% hydrogen peroxide, and other reaction conditions are with embodiment 1~5. The results are shown in Table 3.
[0035] Table 3 Different n(H 2 o 2 / styrene) on the epoxidation reaction
[0036]
[0037] As can be seen in table 3, along with the increase of hydrogen peroxide consumption, styrene conversion % improves, styrene oxide selectivity % and benzaldehyde selectivity % change little, but when n(H 2 o 2 / styrene) exceeds 1, the % increase of styrene conversion rate is not obvious. In order to control the self-decomposition degree of hydrogen peroxide and reduce the danger in the production process, preferably n(H 2 o 2 / styrene) is 0.5~1:1.
[0038] Implementation Ca...
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