514
Erichsen et al. [64] studied the SAPO-5 for methanol to hydrocarbons and effect
of adding benzene as co-reactant. The study showed that most of the products are in
C 3 –C 5 range. The authors reported that the conversion and selectivity of the reactant
depended on the temperature of reaction and not on the feed rate and catalyst deactivation. The authors performed a steady-state isotope transient experiments by
switching the
12
CH 3 OH feed to
13
CH 3 OH after 18 minutes on stream, at time of
switch, methanol conversion was reported as 75%. The study reported immediate
incorporation of
13
C in the alkene products, whereas it took time to incorporate
13
C
in the polymethylated benzenes (polyMBs). Hence polyMBs were not the major
reactant intermediates in the formation of alkenes. When benzene was used as cofeed with methanol, product selectivity toward C 2 –C 3 products increased. When the
co-feeding was added with
13
CH 3 OH, C 2 –C 3 were reported as predominant products
in
12
C. On the other hand, iso-butene and iso-pentene molecules showed larger
amounts of
13
C, indicating two different mechanisms taking place on the catalysts.
Yoo et al. [62] studied the conversion of synthesis gas to dimethyl ether (DME)
over SAPO-5 admixed with Cu/ZnO/Al 2 O 3 catalyst. The admixed SAPO-5 and
SAPO-11 (10% of SAPO composition) showed 55% conversion and 45% stability
toward DME, whereas pure SAPO-5 and SAPO-11 showed 36% and 33% of CO
conversion at 12 h on time of stream.
Jin et al. [65] compared small-, medium-, or large-pore-sized zeolites and SAPO
for methanol to LPG (liquefied petroleum gas) conversions. The catalytic activities
were found in the order ZSM-5 > SAPO-5 > SAPO-34 with respective fields of LPG
fractions as 54.5%, 10.4%, and 3.9%. The selectivity toward alkene was highest for
ZSM-5 (64.3%) compared SAPO-5 (56.2%). The lower activity of SAPO-34 might
be due to pore blocking during the course of reaction.
Frietas et al. [66] studied dodecanoic acid decomposed over microporous
(SAPO-5) and mesoporous (Al-MCM-41) catalysts. The reaction is important
because the pyrolysis or thermal cracking of the oil results in fuel components. The
NH 3 TPD studies on both catalysts showed that SAPO-5 contained more number of
acidic sites compared to Al-MCM-41. Total conversion of dodecanoic acid was
achieved with 78% of aromatics over Al-MCM-41. The high conversion with mesoporous molecular sieve is reported due to accessible pore size and optimum acidity.
Zhang et al. [67] prepared a composite catalyst to utilize the properties of more
than one catalyst, the core/shell structure comprised of ZSM-5 core and SAPO-5
shell. The SEM and TEM images of catalyst showed the presence of both phases.
The catalytic activity of the material was tested on heavy crude oil cracking. The
conversions of heavy oil over ZSM-5, mechanical mixture (SAPO-5 and ZSM-5),
and ZSM-5/SAPO-5 was 76.78%, 77.44%, and 80.03%, respectively. Also ZSM-5/
SAPO-5 showed high selectivity toward ethene, propene, butane, and LPG, indicating that the pores of ZSM-5 and SAPO-5 were well connected and allowed passage
of molecules.
Singh at al [63] prepared composite materials using SAPO-5 secondary building
units (SBU) as precursors. The composite materials showed surface area in the mesoporous range, with the distinct acidity pattern compared to SAPO-5. The catalyst
was tested for 1-octene hydroisomerization in the vapor phase. Above 673 K, the
R. Yadav and A. K. Singh
Erichsen et al. [64] studied the SAPO-5 for methanol to hydrocarbons and effect
of adding benzene as co-reactant. The study showed that most of the products are in
C 3 –C 5 range. The authors reported that the conversion and selectivity of the reactant
depended on the temperature of reaction and not on the feed rate and catalyst deactivation. The authors performed a steady-state isotope transient experiments by
switching the
12
CH 3 OH feed to
13
CH 3 OH after 18 minutes on stream, at time of
switch, methanol conversion was reported as 75%. The study reported immediate
incorporation of
13
C in the alkene products, whereas it took time to incorporate
13
C
in the polymethylated benzenes (polyMBs). Hence polyMBs were not the major
reactant intermediates in the formation of alkenes. When benzene was used as cofeed with methanol, product selectivity toward C 2 –C 3 products increased. When the
co-feeding was added with
13
CH 3 OH, C 2 –C 3 were reported as predominant products
in
12
C. On the other hand, iso-butene and iso-pentene molecules showed larger
amounts of
13
C, indicating two different mechanisms taking place on the catalysts.
Yoo et al. [62] studied the conversion of synthesis gas to dimethyl ether (DME)
over SAPO-5 admixed with Cu/ZnO/Al 2 O 3 catalyst. The admixed SAPO-5 and
SAPO-11 (10% of SAPO composition) showed 55% conversion and 45% stability
toward DME, whereas pure SAPO-5 and SAPO-11 showed 36% and 33% of CO
conversion at 12 h on time of stream.
Jin et al. [65] compared small-, medium-, or large-pore-sized zeolites and SAPO
for methanol to LPG (liquefied petroleum gas) conversions. The catalytic activities
were found in the order ZSM-5 > SAPO-5 > SAPO-34 with respective fields of LPG
fractions as 54.5%, 10.4%, and 3.9%. The selectivity toward alkene was highest for
ZSM-5 (64.3%) compared SAPO-5 (56.2%). The lower activity of SAPO-34 might
be due to pore blocking during the course of reaction.
Frietas et al. [66] studied dodecanoic acid decomposed over microporous
(SAPO-5) and mesoporous (Al-MCM-41) catalysts. The reaction is important
because the pyrolysis or thermal cracking of the oil results in fuel components. The
NH 3 TPD studies on both catalysts showed that SAPO-5 contained more number of
acidic sites compared to Al-MCM-41. Total conversion of dodecanoic acid was
achieved with 78% of aromatics over Al-MCM-41. The high conversion with mesoporous molecular sieve is reported due to accessible pore size and optimum acidity.
Zhang et al. [67] prepared a composite catalyst to utilize the properties of more
than one catalyst, the core/shell structure comprised of ZSM-5 core and SAPO-5
shell. The SEM and TEM images of catalyst showed the presence of both phases.
The catalytic activity of the material was tested on heavy crude oil cracking. The
conversions of heavy oil over ZSM-5, mechanical mixture (SAPO-5 and ZSM-5),
and ZSM-5/SAPO-5 was 76.78%, 77.44%, and 80.03%, respectively. Also ZSM-5/
SAPO-5 showed high selectivity toward ethene, propene, butane, and LPG, indicating that the pores of ZSM-5 and SAPO-5 were well connected and allowed passage
of molecules.
Singh at al [63] prepared composite materials using SAPO-5 secondary building
units (SBU) as precursors. The composite materials showed surface area in the mesoporous range, with the distinct acidity pattern compared to SAPO-5. The catalyst
was tested for 1-octene hydroisomerization in the vapor phase. Above 673 K, the
R. Yadav and A. K. Singh