Investigation of K-promoted Cu-Zn-Al, Cu-X-Al and Cu-Zn-X (X = Cr, Mn) catalysts for carbon monoxide hydrogenation to higher alcohols
Authors: E. Heracleous, E.T. Liakakou, A.A. Lappas, A.A. Lemonidou
Abstract:
In this study, we report the effect of Cu/Zn/Al chemical composition and Zn and/or Al substitution by Mn and/or Cr in K-promoted Cu-Zn-Al catalysts for the hydrogenation of CO to higher alcohols. In terms of higher alcohols, the synthesis yielded preferentially primary 2-methyl branched alcohols with up to five carbon atoms, namely 2-methyl-1-propanol and 2-methyl-1-butanol, together with ethanol and propanol. Variation of the Cu/Zn/Al chemical composition showed that the catalyst with a Cu/Zn atomic ratio of 1 and low Al content(K-Cu45Zn45Al10) exhibits the optimum performance in terms of both activity and selectivity to higher alcohols. High Al contents on the other hand favor methanol production at the expense of higher alcohols. It is postulated that due to its acidic nature, alumina reduces the basic sites on the catalyst, thereby retarding the C1→C2 step. Substitution of Zn and/or Al by Mn and/or Cr was found to reduce activity by ∼50%, probably due to the lower exposed copper surface area as indicated by the formation of larger CuO crystals. In terms of selectivity, the most appreciable changes were recorded for the K-Cu45Zn45Al10 catalyst, where a 50% increase in higher alcohol formation was measured, rendering the catalyst the most selective among the investigated materials. Characterization of the catalysts provided some insight on the beneficial influence of Zn substitution by Mn in the K-Cu45Zn45Al10 sample. Inverse correlation between acidity and higher alcohols selectivity was evidenced, in accordance with the general notion that higher alcohol formation requires basic sites and indicates that reduced acidity is needed for the aldol-type condensation reactions. The replacement of Mn by Zn in K-Cu-Mn-Al reduced acidity and thus promoted the production of the desired higher alcohol products.
Keywords:
CO hydrogenation to higher alcohols
Cu-Zn-Al catalysts
Alkali promotion
Cr promoter
Mn promoter
Acidity
Published in: Applied catalysis A: General (Volume 455, Pages 1-266, 30 March 2013)
Publisher: Elsevier
ISSN Information: 0926-860X
Investigation of K-promoted Cu-Zn-Al, Cu-X-Al and Cu-Zn-X (X = Cr, Mn) catalysts for carbon monoxide hydrogenation to higher alcohols
- Ngày hội Văn hóa đọc lần VI
- Vòng Sơ Khảo Cuộc Thi Đại Sứ Văn Hóa Đọc Năm 2024
- Ngày hội sách “CITTADELLA” khuyến khích và tôn vinh vai trò của sách trong sinh viên Bách khoa
- Cuộc Thi Ảnh “Khoảnh Khắc VNUHCM Libraries”
- Ngày hội văn hóa đọc lần V
- Ngày hội văn hóa đọc lần II
- Ngày hội văn hóa đọc lần IV
- Ngày hội văn hóa đọc lần III
- Tiếp GS Omer Mert Denizci, Trường ĐH Marmara Thổ Nhĩ Kỳ
- Tiếp Cô Claudia Tarzariol Từ The University Of Trento, Italy (Unitrento)
- Tiến sĩ kiều bào Mỹ tặng sách trị giá 150.000 USD cho sinh viên bách khoa
- Khảo sát ý kiến bạn đọc
-
Trực tuyến:11
-
Hôm nay:4825
-
Tuần này:28893
-
Tuần trước:40192
-
Tháng trước:61686
-
Tất cả:4050789