One-pot catalytic conversion of biomass and alkanes [electronic resource] : Kinetically coupling deoxygenation and dehydrogenation pathways

 0 Người đánh giá. Xếp hạng trung bình 0

Tác giả:

Ngôn ngữ: eng

Ký hiệu phân loại: 666.9 Masonry adhesives

Thông tin xuất bản: Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Science ; Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2018

Mô tả vật lý: Size: 10 p. : , digital, PDF file.

Bộ sưu tập: Metadata

ID: 264359

 The stoichiometric hydrogen deficiency of carbohydrate feedstock implies that all conversion processes must remove oxygen and concurrently increase hydrogen content to form liquid hydrocarbon products. With support from the DOE Early Career program (DE-SC0008418) we have investigated the use of transition metal carbides for hydrodeoxygenation (HDO) chemistries using CH<
 sub>
 4<
 /sub>
  and H<
 sub>
 2<
 /sub>
  as co-reactants. We report that concurrently processing CH<
 sub>
 4<
 /sub>
  and C<
 sub>
 1<
 /sub>
 -C<
 sub>
 3<
 /sub>
  oxygenates (oxygenate/CH<
 sub>
 4<
 /sub>
  = 0.01-0.1) at 950 K on molybdenum carbide clusters encapsulated in zeolite micropores results in a staged bed with upstream CH<
 sub>
 4<
 /sub>
  reforming and downstream CH<
 sub>
 4<
 /sub>
  dehydroaromatization. Forward rates of CH<
 sub>
 4<
 /sub>
  pyrolysis limited by CH<
 sub>
 4<
 /sub>
  activation are unperturbed by the introduction of oxygenates with a (C/H)<
 sub>
 eff<
 /sub>
  <
 0.25 after rigorously accounting for the thermodynamic reversibility caused by the H<
 sub>
 2<
 /sub>
  produced in oxygenate reforming reactions and the fraction of the active catalyst bed deemed unavailable for CH<
 sub>
 4<
 /sub>
  dehydroaromatization. A binomial distribution of <
 sup>
 12<
 /sup>
 C/<
 sup>
 13<
 /sup>
 C isotopologues of CO is observed upon introduction of CH<
 sub>
 3<
 /sub>
 <
 sup>
 13<
 /sup>
 COOH/CH<
 sub>
 4<
 /sub>
  reactants suggesting that the introduction of oxygenates with a (C/H)<
 sub>
 eff<
 /sub>
  <
 0.25 results in complete fragmentation of the oxygenate at these temperatures which in turn results in the invariance of forward rates of CH<
 sub>
 4<
 /sub>
  pyrolysis when using CO<
 sub>
 2<
 /sub>
 , HCOOH, or CH<
 sub>
 3<
 /sub>
 COOH co-feeds. The stoichiometric loss of oxygen as CO when co-processing C<
 sub>
 1<
 /sub>
 -C<
 sub>
 3<
 /sub>
  oxygenates and CH<
 sub>
 4<
 /sub>
  at these temperatures demonstrates that (C/H)<
 sub>
 eff<
 /sub>
  =(C-O)/H is a single valued descriptor for oxygen removal on Mo/HZSM-5 catalysts. Separately, we have demonstrated the utility of transition metal carbides for vapor phase catalytic hydrodeoxygenation using molecular hydrogen with high selectivity for C-O cleavage and near absence of sequential hydrogenation reactions at atmospheric hydrogen pressure and illustrated that the faculty of transition metal carbides for selective hydrodeoxygenation arises due to oxygen-modification of the catalyst in situ. The oxophilic characteristics of these materials engender both the observed acid-metal catalytic bifunctionality and selectivity for hydrodeoxygenation. The evolution of catalyst surface composition and catalytic function under oxidative reaction environments proffers unique challenges in structural characterization of these materials and in this context, we developed and demonstrated the use of chemical titration and chemical transient studies to assess catalytic site identity and densities.
Tạo bộ sưu tập với mã QR

THƯ VIỆN - TRƯỜNG ĐẠI HỌC CÔNG NGHỆ TP.HCM

ĐT: (028) 71010608 | Email: tt.thuvien@hutech.edu.vn

Copyright @2024 THƯ VIỆN HUTECH