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FIG. 1. Selectivity vs conversion for FER (a) and silicated alumina ‘b) catalysts.

Figure 1 Selectivity vs conversion for FER (a) and silicated alumina ‘b) catalysts.

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* LHSV = liquid hourly space velocity (liquid feed density = 0.6 g/ml). » Piot= 1 atm; dilution with isobutane. “t; and tz are the times on stream of starting and stopping product collection, respectively. 4 A} aromatics, but maily C8 aromatics. ° Nonaromatic hydrocarbons. n-Butene C onversion Data on Various Catalysts Belonging to the Si02- Al203 System
* LHSV = liquid hourly space velocity (liquid feed density = 0.6 g/ml). » Piot= 1 atm; dilution with isobutane. “t; and tz are the times on stream of starting and stopping product collection, respectively. 4 A} aromatics, but maily C8 aromatics. ° Nonaromatic hydrocarbons. n-Butene C onversion Data on Various Catalysts Belonging to the Si02- Al203 System
Characteristics of the Catalysts under Study The HZSM5 sample was from Engelhard (Si/A1 atomic ratio = 23).
Characteristics of the Catalysts under Study The HZSM5 sample was from Engelhard (Si/A1 atomic ratio = 23).
are shown. The spectra of pure silica samples (Fig. 2g) are just coincident, showing a single sharp band at 3745 cm~!, in agreement with a number of previous data, as reviewed some years ago (30, 31). This band is certainly dominated by the absorption due to the O-H stretching mode of a sin- gle terminal Si-OH group (Scheme 1, Species I), although it is agreed today that it also contains the O-H stretchings
are shown. The spectra of pure silica samples (Fig. 2g) are just coincident, showing a single sharp band at 3745 cm~!, in agreement with a number of previous data, as reviewed some years ago (30, 31). This band is certainly dominated by the absorption due to the O-H stretching mode of a sin- gle terminal Si-OH group (Scheme 1, Species I), although it is agreed today that it also contains the O-H stretchings
FIG.2. FT-IR spectra of the catalysts HZSM5 (a), FER1 (b), FER2 (c), AS (d), SA 13 (e), SA8 (f), S2 (g) in the O-H stretching region after outgassing at 873K.
FIG.2. FT-IR spectra of the catalysts HZSM5 (a), FER1 (b), FER2 (c), AS (d), SA 13 (e), SA8 (f), S2 (g) in the O-H stretching region after outgassing at 873K.
FIG.3. FT-IR spectra (4000-2100 cm!) of the catalysts HZSM5 (a), FER1(b),A S(c), SA 13(d), SA 8(e), $2 (f) at 300K in contact with acetonitrile vapour (10 Torr).
FIG.3. FT-IR spectra (4000-2100 cm!) of the catalysts HZSM5 (a), FER1(b),A S(c), SA 13(d), SA 8(e), $2 (f) at 300K in contact with acetonitrile vapour (10 Torr).
FIG. 4. FT-IR spectra (4000-2100 cm~!) of the catalysts HZSM5 (a), FER1 (b), AS (c), SA 13 (d), SA 8 (e), S2 (f) after acetonitrile adsorption at 300 K and successive outgassing at 300 K.
FIG. 4. FT-IR spectra (4000-2100 cm~!) of the catalysts HZSM5 (a), FER1 (b), AS (c), SA 13 (d), SA 8 (e), S2 (f) after acetonitrile adsorption at 300 K and successive outgassing at 300 K.
FIG.5. Subtraction FT-IR spectra relative to adsorption of AN onA S:(a) upon contact with A N vapor (10 Torr) with the spectrum of the activate catalyst subtracted; (b) upon contact with A N vapor (10 Torr) and the spectrum of the outgassed catalyst subtracted; and (c) after outgassing at roon temperature with the spectrum of the activated catalyst subtracted.
FIG.5. Subtraction FT-IR spectra relative to adsorption of AN onA S:(a) upon contact with A N vapor (10 Torr) with the spectrum of the activate catalyst subtracted; (b) upon contact with A N vapor (10 Torr) and the spectrum of the outgassed catalyst subtracted; and (c) after outgassing at roon temperature with the spectrum of the activated catalyst subtracted.
Summary of the Data on the Catalysts Lewis A cidity
Summary of the Data on the Catalysts Lewis A cidity
T des = Temperature for the desorption upon outgassing; H = hydrogen bonding; P = protonation. Summary of the Data on the Catalysts Bronsted A cidity
T des = Temperature for the desorption upon outgassing; H = hydrogen bonding; P = protonation. Summary of the Data on the Catalysts Bronsted A cidity
FIG.6. FT-IR spectra in the C=N stretching region of the adsorbed species arising from acetonitrile adsorption on the catalysts HZSM5 (a), FER1 (b), SA 13 (c), AS (d), and S (e); for each catalyst, the upper spectra are recorded at 300 K in contact with the gas, the lower after further outgassing at 300 K.
FIG.6. FT-IR spectra in the C=N stretching region of the adsorbed species arising from acetonitrile adsorption on the catalysts HZSM5 (a), FER1 (b), SA 13 (c), AS (d), and S (e); for each catalyst, the upper spectra are recorded at 300 K in contact with the gas, the lower after further outgassing at 300 K.
FIG. 7. FT-IR spectra of the surface species arising from adsorption of pyridine on a silica-alumina cracking catalyst (13% A 1,03, from Strem) at r.t. (a) and after outgassing at 373 K (b).
FIG. 7. FT-IR spectra of the surface species arising from adsorption of pyridine on a silica-alumina cracking catalyst (13% A 1,03, from Strem) at r.t. (a) and after outgassing at 373 K (b).
FIG. 8. FT-IR spectra of the surface hydroxy groups of a silica-alumina cracking catalyst (13% A1,03, from Strem) after activation at 623 K (a), after contact with pyridine vapor and outgassing at r.t. (b), and after outgassing at 373 K (c).
FIG. 8. FT-IR spectra of the surface hydroxy groups of a silica-alumina cracking catalyst (13% A1,03, from Strem) after activation at 623 K (a), after contact with pyridine vapor and outgassing at r.t. (b), and after outgassing at 373 K (c).
FIG.9. FT-IR spectra of the adsorbed species arising from contact of FER1 (a) and HZSM5 (b) with Py vapor (3 Torr) and successive outgassing it 473 K.
FIG.9. FT-IR spectra of the adsorbed species arising from contact of FER1 (a) and HZSM5 (b) with Py vapor (3 Torr) and successive outgassing it 473 K.
FIG.10. FT-IR spectra of the surface hydroxy groups of FER1 after activation (a) and after contact with pyridine and successive outgassing at 373 K (b) and 473 K(c). (d) is the subtraction (c - a) showing the perturbation arising from pyridine adsorbed species still existing at 473 K.
FIG.10. FT-IR spectra of the surface hydroxy groups of FER1 after activation (a) and after contact with pyridine and successive outgassing at 373 K (b) and 473 K(c). (d) is the subtraction (c - a) showing the perturbation arising from pyridine adsorbed species still existing at 473 K.
SCHEME 3. Reaction network for 2-butene skeletal isomerization based on the main product.
SCHEME 3. Reaction network for 2-butene skeletal isomerization based on the main product.
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Chemical EngineeringCatalysisHeterogeneous CatalysisInfrared SpectrometryFT IR Spectroscopy
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