الفهرس 
Effect of the type of zeolites catalysts for 4Only 14 pages are availabe for public view
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Abstract
The thesis contains five parts, each concerned with a
conversion of methanol to dimethyl ether on zeolite cataltst.
Part I: In this part, four different zeolite were used to
investigate there activity on DME formation (H-ZSM-5, HMOR,
H-BETA and H-Y), its found that H-ZSM-5 zeolite
catalyst has higher catalytic activity than the other three zeolite
catalyst. This order is compatible with the order of acidity of
this zeolite that H-ZSM-5 has stronger acidity than the other
zeolites.
Part II: In this part we studied the effect of Si/Al ratio on HZSM-
5 and H-MOR zeolite catalyst for conversion of methanol
to DME, we studied five samples of H-ZSM-5 zeolite
possessing five different Si/Al ratios (25, 90, 120, 240 and 400)
and three samples of H-MOR zeolite (6.1, 40, 90), increase
Si/Al ratio leads to decrease the catalytic activity due to
decrease acidity, so HZSM-5(25) and H-MOR(6.1) have
highest activity.
Part III: In this part the effect of ultrasonic irradiation were
studied on zeolite catalysts:
1-Study the factors affecting ultrasonication efficiency were
studied on H-MOR catalyst, effect of ultrasonic irradiation
time (20, 40, 60, 80, 100 min), effect of type of solvent
(methanol, ethanol, propanol , butanol and warer), effect of
volume of solvent (5, 7.5, 10 and 12.5 cm3), its found that the
best condition to use ultrasonic irradiation is 60 min, 7.5 cm3
methanol.
2- The best condition of ultrasonication was studied on other
zeolite catalyst H-BETA, H-Y, H-ZSM-5 with different Si/Al
ratio. Ultrasonic increase the catalytic activity of H-BETA and
H-ZSM-5 different Si/Al ratio, but result little decrease in the
catalytic activity of H-Y zeolite.
Part IV: In this part the effect of halogenation (chlorination
and fluorination) and effect of ultrasonic on halogenation were
studied on zeolite catalysts.
1-H-MOR: Halogenation of H-MOR either by F- or Cl- was
found to promote its activity for conversion of methanol due to
increasing the acidity.
H-MOR (F) > H-MOR (Cl) > H-MOR
The fluorinated H-MOR zeolite catalysts are the most active
and selective catalysts for conversion of methanol to DME.
Ultrasonic irradiation leads to increase the catalytic activity of
chlorinated H-MOR, but decrease the activity of fluorinated HMOR.
2-H-ZSM-5(25): Both chlorination and fluorination increase
the catalytic activity of H-ZSM-5(25) zeolite but H-ZSM-5(Cl)
has higher activity than H-ZSM-5(F), ultrasoniction increase
the catalytic activity of chlorinated H-ZSM-5(25), but decrease
the activity of fluorinated H-ZSM-5(25).
3- HZSM-5(400): Halogenation increase the activity of HZ
(400), fluorinated sample has higher activity than chlorinated
one, ultrasonication increase the activity of both chlorinated
and fluorinated H-ZSM-5(400) samples.
4- H-Y: Halogenation increases the activity of H-Y zeolite the
activities of the current catalysts can be arranged in the order:
HY (Cl) > HY (F) > HY
Sonication treatment of halogenated H-Y sample HY (Cl) has
higher activity than H-Y (Cl), moreover sonicated H-Y (F) has
lower activity than HY (F).
Part V: The effect of microwave irradiation time (20, 40, 60
and 80 sec) were studied on H-MOR zeolite catalyst ,
microwave treatment by 20 sec has higher activity than other
microwave times, that increase microwave time leads to
decrease the catalytic activity of H-MOR catalyst due to
increase crystal size and decrease surface area.