A kind of preparation method of isoprene
A technology for isoprene and isobutylene, which is applied in the field of Pr-doped ceria catalyzing the reaction of isobutylene and formaldehyde solution to prepare isoprene, can solve the problems that need to be further improved, and achieves controllable reaction process, easy operation and reaction. The effect of simple process and simple separation process
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Embodiment 1
[0046] Example 1 Cerium nitrate and praseodymium nitrate are dissolved in water at a molar ratio of 99:1 to obtain an aqueous solution of cerium nitrate and praseodymium nitrate. The concentration of the two metal ions in the aqueous solution sums to 1mol / L, and then under stirring conditions, at 25 At ℃, 38wt% ammonia water was added dropwise thereto, and the molar ratio of ammonia water to the sum of the moles of the two metal ions was 10:1, then stood, separated, washed with water and ethanol, dried, and then calcined at 300 °C for 2 hours, Available Pr-doped ceria catalyst (Pr doping amount 0.8wt%) is recorded as Pr-CeO 2 -99.
[0047] Fill 2g of 40-60 mesh Pr-doped ceria prepared above into a fixed-bed reactor, gasify isobutylene and formaldehyde aqueous solution and mix with N 2 Mixed, passed into a fixed bed as a reaction gas, wherein the volume fraction of isobutene and formaldehyde were 5% and 5% respectively; the mass space velocity of the catalyst was 0.3h -1 . T...
Embodiment 2
[0049] Dissolve cerium nitrate and praseodymium nitrate in water at a molar ratio of 49:1 to obtain an aqueous solution of cerium nitrate and praseodymium nitrate. The sum of the concentrations of the two metal ions in the aqueous solution is 0.1mol / L. Add sodium hydroxide to it, the molar ratio of sodium hydroxide to the sum of the moles of the two metal ions is 5:1, then let it stand, separate, wash with water and ethanol, dry, and then roast at 500 °C for 4h, Available Pr-doped ceria catalyst (Pr doping amount 1.6wt%), denoted as Pr-CeO 2 -49.
[0050] Fill 40-60 mesh 2g of the above-mentioned Pr-doped ceria into a fixed-bed reactor, gasify isobutene and formaldehyde aqueous solution and mix with Ar, and pass it into the fixed bed as reaction gas, wherein the volume of isobutene and formaldehyde The fractions are 5% and 5% respectively; the mass space velocity of the catalyst is 0.3h -1 . The reaction was continuously fed at 200°C under a pressure of 0.5 atm. After the ...
Embodiment 3
[0052] Dissolve cerium nitrate and praseodymium nitrate in water at a molar ratio of 19:1 to obtain an aqueous solution of cerium nitrate and praseodymium nitrate. The concentration of the two metal ions in the aqueous solution is 0.05mol / L. Then, under stirring conditions, at 85°C, Add potassium hydroxide dropwise to it, the molar ratio of potassium hydroxide to metal ions is 3:1, then let stand, separate, wash with water and ethanol, dry, and then roast at 800°C for 8h to obtain Pr-doped dioxide The cerium catalyst (the doping amount of Pr is 4wt%) is denoted as Pr-CeO 2 -19.
[0053] 40-60 mesh 2g of the Pr-doped ceria prepared above is packed into a fixed-bed reactor, isobutene and trioxane methanol solution are gasified and mixed with He, and passed into the fixed bed as a reaction gas, wherein isobutene, The volume fraction of formaldehyde is 25% and 5% respectively; the mass space velocity of the catalyst is 1h -1 . The reaction was continuously fed at 250°C under a ...
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