ZEOLITE Y
Process for preparing a modified zeolite Y which process comprises subjecting zeolite Y having a silica to alumina molar ratio of at least 10 to calcination at a temperature of from 700 to 1000° C. wherein (i) the steam partial pressure is at most 0.06 bar at a temperature of from 700 to 800° C., (ii) the steam partial pressure is at most 0.08 bar at a temperature of from 800 to 850° C. , (iii) the steam partial pressure is at least 0.03 bar at a temperature of from 850 to 900° C., and (iv) the steam partial pressure is at least 0.05 bar at a temperature of from 900 to 950° C. and (v) the steam partial pressure is at least 0.07 bar at a temperature of from 950 to 1000° C., a modified zeolite Y obtainable by such process, zeolite Y having a silica to alumina molar ratio of at least 10, the infrared spectrum of which has a peak at 3700 cm −1 but substantially no peaks at 3605 and 3670 cm −1 and zeolite Y having a silica to alumina molar ratio of at least 10, which zeolite Y has an acidity as measured by exchange with perdeuterated benzene of at most 20 micromole/gram.
1 . A process for preparing a modified zeolite Y which process comprises subjecting zeolite Y having a silica to alumina molar ratio of at least 10 to calcination at a temperature of from 700 to 1000° C. wherein (i) the steam partial pressure is at most 0.06 bar at a temperature of from 700 to 800° C., (ii) the steam partial pressure is at most 0.08 bar at a temperature of from 800 to 850° C. , (iii) the steam partial pressure is at least 0.03 bar at a temperature of from 850 to 900° C., and (iv) the steam partial pressure is at least 0.05 bar at a temperature of from 900 to 950° C. and (v) the steam partial pressure is at least 0.07 bar at a temperature of from 950 to 1000° C.
2 . A process according to claim 1 , in which process the zeolite Y has a silica to alumina molar ratio of more than 10.
3 . A process according to claim 2 , in which process the calcination is carried out during a time of from 20 minutes to 5 hours.
4 . A process according to claim 3 , in which process the zeolite Y before calcination has a bulk silica to alumina molar ratio of greater than 13, a unit cell size in the range of from 24.10 to 24.40 Å, and a surface area of at least 875 m 2 /g.
5 . A modified zeolite Y prepared by subjecting zeolite Y having a silica to alumina molar ratio of at least 10 to calcination at a temperature of from 700 to 1000° C. wherein (i) the steam partial pressure is at most 0.06 bar at a temperature of from 700 to 800° C., (ii) the steam partial pressure is at most 0.08 bar at a temperature of from 800 to 850° C. , (iii) the steam partial pressure is at least 0.03 bar at a temperature of from 850 to 900° C., and (iv) the steam partial pressure is at least 0.05 bar at a temperature of from 900 to 950° C. and (v) the steam partial pressure is at least 0.07 bar at a temperature of from 950 to 1000° C.
6 . The modified zeolite Y of claim 5 wherein the zeolite Y has a silica to alumina molar ratio of more than 10.
7 . The modified zeolite Y of claim 6 , wherein the calcination of the zeolite Y is carried out during a time of from 20 minutes to 5 hours.
8 . The modified zeolite Y of claim 7 , wherein the zeolite Y before calcination has a bulk silica to alumina molar ratio of greater than 13, a unit cell size in the range of from 24.10 to 24.40 A, and a surface area of at least 875 m 2 /g.
9 . A zeolite Y having a silica to alumina molar ratio of at least 10, the infrared spectrum of which has a peak at 3700 cm −1 but substantially no peak at 3670 cm −1 .
10 . A zeolite Y having a silica to alumina molar ratio of at least 10, which zeolite Y has an acidity as measured by exchange with perdeuterated benzene of at most 20 micromole/gram.
11 . The zeolite Y according to claim 10 , which zeolite Y has an acidity as measured by exchange with perdeuterated benzene of at most 10 micromole/gram.
12 . A method of using a zeolite, wherein a modified zeolite Y prepared by subjecting zeolite Y having a silica to alumina molar ratio of at least 10 to calcination at a temperature of from 700 to 1000° C. wherein (i) the steam partial pressure is at most 0.06 bar at a temperature of from 700 to 800° C., (ii) the steam partial pressure is at most 0.08 bar at a temperature of from 800 to 850° C. , (iii) the steam partial pressure is at least 0.03 bar at a temperature of from 850 to 900° C., and (iv) the steam partial pressure is at least 0.05 bar at a temperature of from 900 to 950° C. and (v) the steam partial pressure is at least 0.07 bar at a temperature of from 950 to 1000° C. is used as an adsorbent.
13 . The modified zeolite Y of claim 12 wherein the zeolite Y has a silica to alumina molar ratio of more than 10.
14 . The modified zeolite Y of claim 13 , wherein the calcination of the zeolite Y is carried out during a time of from 20 minutes to 5 hours.
15 . The modified zeolite Y of claim 14 , wherein the zeolite Y before calcination has a bulk silica to alumina molar ratio of greater than 13, a unit cell size in the range of from 24.10 to 24.40 A, and a surface area of at least 875 m 2 /g.
16 . A method of using a zeolite, wherein a modified zeolite Y having a silica to alumina molar ratio of at least 10, the infrared spectrum of which has a peak at 3700 cm −1 but substantially no peak at 3670 cm −1 is used as an adsorbent.
17 . A method of using a zeolite, wherein a modified zeolite Y having a silica to alumina molar ratio of at least 10, which zeolite Y has an acidity as measured by exchange with perdeuterated benzene of at most 20 micromole/gram is used as an adsorbent.