Propylene Dimerization Over Nickel-Ion Exchanged Zeolites in the Liquid Phase

Mina K. MUNSHIEVA

Makale detayları

Propylene Dimerization Over Nickel-Ion Exchanged Zeolites in the Liquid Phase

Yazarlar:

Mina K. MUNSHIEVA

Yayıncı:

TUBITAK

Dergi:

Turkish Journal of Chemistry 2001 Vol.25 Issue 4, pp.419-424

Belge Tipi:

Makale

Yayın Tarihi:

3/2001

Belge Dili:

Türkçe

Document ID (Org No.):

2000730033

Sıklık:

İki Aylık

eISSN:

1303-6130

pISSN:

1300-0527

Özet:

 

The possibility of the dimerization of propylene in the  liquid phase over nickel-ion exchanged zeolites (Ni-zeolites) modified  by treatment with AlEt2Cl to provide enhanced activity is  studied.    In order to determine the influence of the crystalline structure of   zeolites on their catalytic activity and the selection of the most   active catalyst the zeolites of faujasite (NaX, NaY), eryonite and   mordenite types with various structures and different cell sizes have   been chosen. The samples of Ni-zeolites were prepared by ion exchange   with nickel nitrate in a corresponding zeolite. The treatment of   these zeolites with AlEt2Cl leads to the formation of active   dimerization of propylene catalytic systems. The activity of these   systems reaches the maximum at an Al/Ni weight ratio approximately   equal to 10.    It is assumed that the mechanism of propylene dimerization in the   investigated catalysts is similar to the mechanism of olefin   dimerization in Ziegler-Natta catalytic systems. The ESR results   suggests Ni-ion participation in the formation of catalytically   active species.    The distinctions in the catalytic behaviour of the studied zeolites   are connected with their crystalline structure. It is probable that   the dimerization process over Ni-zeolites of faujasite type goes on   in the kinetic area, while in the case of Ni-eryonite and   Ni-mordenite, diffusional breaking, which decreases an activity of   these catalysts, takes place.    The diffractographic investigation demonstrates a partial destruction   of the crystalline structure of zeolite after the repeated treatment   with AlEt2Cl. The preservation of the crystalline structure from   full decay presumably is the consequence of the exchanged reaction   between the Ni-ion and proton - product of the interaction of   Ni-zeolite with AlEt2Cl.

 

The possibility of the dimerization of propylene in the  liquid phase over nickel-ion exchanged zeolites (Ni-zeolites) modified  by treatment with AlEt2Cl to provide enhanced activity is  studied.    In order to determine the influence of the crystalline structure of   zeolites on their catalytic activity and the selection of the most   active catalyst the zeolites of faujasite (NaX, NaY), eryonite and   mordenite types with various structures and different cell sizes have   been chosen. The samples of Ni-zeolites were prepared by ion exchange   with nickel nitrate in a corresponding zeolite. The treatment of   these zeolites with AlEt2Cl leads to the formation of active   dimerization of propylene catalytic systems. The activity of these   systems reaches the maximum at an Al/Ni weight ratio approximately   equal to 10.    It is assumed that the mechanism of propylene dimerization in the   investigated catalysts is similar to the mechanism of olefin   dimerization in Ziegler-Natta catalytic systems. The ESR results   suggests Ni-ion participation in the formation of catalytically   active species.    The distinctions in the catalytic behaviour of the studied zeolites   are connected with their crystalline structure. It is probable that   the dimerization process over Ni-zeolites of faujasite type goes on   in the kinetic area, while in the case of Ni-eryonite and   Ni-mordenite, diffusional breaking, which decreases an activity of   these catalysts, takes place.    The diffractographic investigation demonstrates a partial destruction   of the crystalline structure of zeolite after the repeated treatment   with AlEt2Cl. The preservation of the crystalline structure from   full decay presumably is the consequence of the exchanged reaction   between the Ni-ion and proton - product of the interaction of   Ni-zeolite with AlEt2Cl.

Makale detayları

Propylene Dimerization Over Nickel-Ion Exchanged Zeolites in the Liquid Phase

Yazarlar: Mina K. MUNSHIEVA

Yayıncı: TUBITAK

Dergi: Turkish Journal of Chemistry 2001 Vol.25 Issue 4, pp.419-424

Belge Tipi: Makale

Yayın Tarihi: 3/2001

Belge Dili: Türkçe

Document ID (Org No.): 2000730033

Sıklık: İki Aylık

eISSN: 1303-6130

pISSN: 1300-0527

Sayı

Yazarlar:

Mina K. MUNSHIEVA

Yayıncı:

TUBITAK

Dergi:

Turkish Journal of Chemistry 2001 Vol.25 Issue 4, pp.419-424

Belge Tipi:

Makale

Yayın Tarihi:

3/2001

Belge Dili:

Türkçe

Document ID (Org No.):

2000730033

Sıklık:

İki Aylık

eISSN:

1303-6130

pISSN:

1300-0527