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Teabag technology in long chain alkane selective oxidation

Shang, Yuan 2014. Teabag technology in long chain alkane selective oxidation. PhD Thesis, Cardiff University.
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Abstract

This thesis describes the searching, preparation, characterization and catalytic evaluation of active catalysts for the terminal selectivity of long chain linear alkanes. The focus of the thesis is the study of shape selective materials, including the organic material cyclodextrins, and the inorganic material, zeolite and zeolitic membranes. Prepared catalysts were performed with n-decane or n-hexane as models to produce the terminal oxidation products 1-decanol, 1-hexanol, decanoic acid and hexanoic acid. Studies with the Andrews glass reactor showed a stable terminal selectivity of 5%-9% in the autoxidation of n-hexane in short time reactions. A comparison between the Andrews glass reactor and Parr stainless steel reactor showed that the autoxidation reactions can get higher conversion but lower terminal selectivity in the stainless steel reactor than the glass reactor. Most of the metal/support catalysts showed very low conversion and very poor terminal selectivity. Increasing the temperature leads to higher conversion but results in more cracked products and less selectivity for oxygenated C10 products. The most active catalyst was 5 w.t.% Au/TiO2. However, these catalysts did not show good terminal alcohol selectivity (<3%); whereas the cracked acid selectivity was high (32.0%). Cyclodextrin covered Au/SiO2 catalysts showed limited changes in terminal selectivities (1-2%). Zeolite 4A, silicalite-1, ZSM-5, zeolite X/Y coated catalysts were successfully synthesized with alumina and silica sphere supports. The most attractive oxidation results were performed by zeolite X/Y and zeolite 4A coated silica catalysts in n-hexane liquid phase oxidation, iv especially for with short reaction time. With zeolite X/Y membrane, in a 30 min reaction, the terminal selectivity was 16%, while the terminal selectivity for the blank reactions was 0-9%. With longer reaction time, the terminal selectivity decreased to 6-7%. Zeolite 4A membrane can produce a terminal selectivity of 13% in 4 h reactions.

Item Type: Thesis (PhD)
Status: Unpublished
Schools: Chemistry
Subjects: Q Science > QD Chemistry
Date of First Compliant Deposit: 30 March 2016
Last Modified: 19 Mar 2016 23:48
URI: https://orca.cardiff.ac.uk/id/eprint/66336

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