The bands due to stretching of OH groups of all four crystalline modifications of cellulose have been measured using a deuteration technique which enables crystalline regions to be studied independently of amorphous regions. Cellulose III prepared from cellulose I (IIII) was found to be different from cellulose III prepared from cellulose II (IIIII). Similarly different cellulose IV's were obtained from celluloses I and II (IVI and IVII). However, the infrared spectra suggest that only one of these, namely, IIII should be regarded as having a crystal structure distinctively different from those of cellulose I and II. Thus IVI and IIIII closely resemble celluloses I and II, respectively, while IVII shows a diffuse absorption and may well possess a disordered lattice. The bearing of these results on the crystal structures of celluloses I and II is discussed. The unit cells of celluloses IIIII and II are different, although their infrared spectra are very similar. These facts suggest that hydrogen bonding in these two forms is of the layer type in the (101) plane, though the possibility of hydrogen bonding in the (101) plane cannot be entirely eliminated.

Biomass processing to value-added chemicals and biofuels received considerable attention due to the renewable nature of the precursors. Here, we report the development of Ru-containing magnetically recoverable catalysts for cellulose hydrogenolysis to low alcohols, ethylene glycol (EG) and propylene glycol (PG). The catalysts are synthesized by incorporation of magnetite nanoparticles (NPs) in mesoporous silica pores followed by formation of 2 nm Ru NPs. The latter are obtained by thermal decomposition of ruthenium acetylacetonate in the pores. The catalysts showed excellent activities and selectivities at 100% cellulose conversion, exceeding those for the commercial Ru/C. High selectivities as well as activities are attributed to the influence of Fe3O4 on the Ru(0)/Ru(4+) NPs. A facile synthetic protocol, easy magnetic separation, and stability of the catalyst performance after magnetic recovery make these catalysts promising for industrial applications.

Observations on the x‐ray scattering by ball‐milled cellulose and cellulose derivatives, amorphous oligosaccharides, and Fortisan H are reported and an approximate shape is established for the scattering curve of the noncrystalline component of celluloses. Using this shape measurements have been made of the minimum crystallinity which is consistent with the observed x‐ray diagram of regenerated cellulose.From a comparison of this minimum crystallinity with crystallinity determined by the infrared‐deuteration method, it is concluded that at least 14% of the total material cannot be truly described as either perfectly crystalline or perfectly amorphous. This fraction of material of intermediate order is registered as crystalline by x‐ray diffraction, but infrared spectroscopy suggests that it does not possess the precise molecular configuration characteristic of crystalline material. Support for this view of structure is reported from observations of differences in hydrogen‐bonding in amorphous regions of regenerated and bacterial celluloses. Infrared results show that OH groups which lie in the surface of crystallites are hydrogen‐bonded in a random amorphous manner and it is concluded that the material of intermediate order can be accounted for in terms of chains lying in the surface of crystallites of cross‐section 29 A. × 65 A.

A method has been developed for determining the accessibility of cellulose to liquid heavy water; the extent of the exchange reaction being measured by determining the change in the refractive index of the heavy water. It is shown that previous work using a slightly different method involved either large experimental errors or the use of unjustified assumptions. In this work an attempt has been made to avoid both these sources of error. A method has also been developed for determining the absolute crystallinity of a cellulose sample. In this method, cellulose is deuterated by D20 vapour until all the amorphous regions have been deuterated as shown by infra-red spectroscopy. The deuterium that has exchanged with the cellulose is then extracted with liquid H20 and the amount determined by measuring the refractive index of the mixture. This technique has advantages in that limitations are not imposed by the thickness or the orientation of samples as in spectroscopic work.

Permanent WRAP URL:http://wrap.warwick.ac.uk/91922 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL' above for details on accessing the published version and note that access may require a subscription. AbstractLiquid-phase hydrogenation of a solution of furfural, phenol and acetic acid has been studied in the 50-235 o C range over magnetic Ru/Fe3O4-SiO2 catalyst targeting the renewable production of second generation biofuels with minimum hydrogen consumption.Phenol was fully hydrogenated to cyclohexanol in the entire temperature range. Below 150 o C, furfural was mainly hydrogenated to tetrahydrofurfuryl alcohol while hydrogenolysis to cyclopentanol was the main reaction pathway above 200 o C. The hydrogenation rate was doubled in an acidic solution (pH=3) as compared to that at a pH 6. The spent catalyst was regenerated and reused in subsequent catalytic runs.

(2016) Metal oxide-zeolite composites in transformation of methanol to hydrocarbons : do iron oxide and nickel oxide matter? RSC Advances, 6 (79). pp. 75166-75177. Permanent WRAP URL:http://wrap.warwick.ac.uk/81920 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work of researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher statement:First published by Royal Society of Chemistry 2016 http://dx.doi.org/10.1039/C6RA19471K A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription. ABSTRACT: The methanol-to-hydrocarbon (MTH) reaction received considerable attention as utilizing renewable sources of both value-added chemicals and fuels becomes number one priority for the society. Here, for the first time we report the development of hierarchical zeolites (ZSM-5) containing both iron oxide and nickel oxide nanoparticles. Modifying the iron oxide (magnetite, Fe3O4) amounts, we are able to control the catalyst activity and the product distribution in the MTH process. At the medium Fe3O4 loading, the major fraction is composed of the C9-C11 hydrocarbons (gasoline fraction). At the higher Fe3O4 loading, the C1-C4 hydrocarbons prevail in the reaction mixture, while at the lowest magnetite loading the major component is the C5-C8 hydrocarbons. Addition of Ni species to Fe3O4-ZSM-5 leads to the formation of mixed Ni oxides (NiO/Ni2O3) positioned either on top or next to Fe3O4 nanoparticles. This modification allowed us to significantly improve the catalyst stability due to diminishing coke formation and disordering of the coke formed. The incorporation of Ni oxide species also leads to a higher catalyst activity (up to 9.3 g(Methanol)/(g(ZSM-5)×h) and an improved selectivity (11.3% of the C5-C8 hydrocarbons and 23.6% of the C9-C11 hydrocarbons), making these zeolites highly promising for industrial applications.

A study of the electron diffraction diagram of Valonia ventricosa cellulose has confirmed the conclusions reached by Honjo and Watanabe concerning the size of its unit cell. The a and c axes of the cell are twice the length of those usually accepted for cellulose I. The symmetry of the cell is P1, but the evidence available at present does not allow a decision to be made concerning the symmetry of the molecular chains. Consideration of x‐ray diffraction and infrared spectroscopic data suggests that bacterial cellulose probably has the same unit cell as Valonia ventricosa, but that other native celluloses may have different cells.

The interaction between cellulose and heavy water allows absorptions due to stretching of OH groups in crystalline and amorphous regions to be studied independently. Crystalline regions give several absorption bands in the 3600–3000 cm.−1 range and it is shown that all the bands are due to stretching of OH groups. Arguments are presented that support the idea that these bands can be interpreted in terms of vibrations of individual groups. It is shown that all the OH groups in crystalline regions of regenerated and bacterial celluloses are hydrogen‐bonded, and that crystal structures suggested by Peirce for these celluloses are incorrect. Suggestions are made about the types of hydrogen bond present in regenerated cellulose. The relationship between infra‐red absorption frequencies and O……O distances in crystals is discussed. It is concluded that no reliable estimate of O……O distances in cellulose can be made from absorption frequencies on the basis of results available at present.