Dehydration of alcohols on crystalline silicates
A technology for ethanol dehydration and ethanol, which is applied in the direction of physical/chemical process catalysts, bulk chemical production, carbon compound catalysts, etc., and can solve the problems of ethylene yield reduction and other issues
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no. 2 approach
[0146] Regarding a second embodiment, it relates to a method of dehydrating at least one alcohol to produce at least one olefin, the method comprising:
[0147] introducing stream (A) comprising at least one alcohol, optionally water, optionally inert components into a reactor; in said reactor under conditions effective to dehydrate at least a portion of said alcohol to produce olefins contacting the stream with a catalyst;
[0148] The olefin-containing stream (B) is recovered from the reactor,
[0149] in
[0150] The catalyst is a phosphorus-modified zeolite,
[0151] The temperature is 280℃~500℃,
[0152] The specific description is the same as above except for WHSV.
[0153] The WHSV of the alcohol is advantageously 0.1-20h -1 , more advantageously 0.5~20h -1 , preferably 0.5~15h -1 , more preferably 0.7~12h -1 .
[0154] The detailed description of the first embodiment is applicable to the second embodiment mutatis mutandis.
[0155] Those skilled in the art wi...
Embodiment 1
[0165] Example 1 (comparative example): γ-Al 2 O 3
[0166] γ-Al as 1.5mm extrudate 2 O 3 Presents the following structural properties: 285m 2 / g specific surface area, the pore distribution is concentrated at about and a pore volume of 0.67 ml / g. The impurities present in small amounts on the alumina are summarized as follows: 0.51 wt % S, 0.4 wt % Si, 0.04 wt % Ca, 0.08 wt % Cl, 0.02 wt % Fe, 0.01 wt % Cu.
[0167] Catalyst performance:
[0168] For the following experiments, a pure ethanol feed was used.
[0169] - at 400°C, at 1.35 bar absolute and in use for 1.8h -1 ethanol space velocity, the ethanol conversion is almost complete (>99.7 wt%), where C 2 ＝ Selectivity of 80% by weight (based on CH 2 ) and C 2 ＝ Purity remained above 98.2 wt%.
[0170] limited C 2 ＝ The selectivity can be explained by the fact that, under these operating conditions, the formation of heavier compounds occurs, especially up to 12% by weight (based on CH 2 ) of C 4 ＝ Olefin...
Embodiment 2
[0176] Example 2 (comparative example): silica-alumina
[0177] Silica-alumina in powder form exhibits 377m 2 / g specific surface area and consists of 94.4 wt% Al 2 O 3 and 5.6 wt% SiO 2 composition.
[0178] The catalyst was first calcined at 600°C in air for 2 hours before loading.
[0179] Catalyst performance:
[0180] For the following experiments, a pure ethanol feed was used.
[0181] - at 400°C, at 1.35 bar absolute and in use for 2.8h -1 ethanol space velocity, the ethanol conversion is almost complete (>99.9 wt%) with C 2 ＝ Selectivity of 90% by weight (based on CH 2 ) and C 2 ＝ Purity remains above 99% by weight.
[0182] with γ-Al 2 O 3 In comparison, better performance was achieved in terms of selectivity and purity. But this time C 4 ＝ The amount of olefin is still very high (~6 wt% (based on CH) 2 )C 4 ＝ ).
[0183] The results are shown in Figures 4 to 6 middle.
[0184] Figure 4 -Ethanol conversion and C 2 ＝ Yield (weight, based on CH...
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