01648nas a2200145 4500008004100000245008400041210006900125260000800194300001400202490000700216520112800223100002401351700002201375856010501397 2014 eng d00aFunction of metals and supports on the hydrodeoxygenation of phenolic compounds0 aFunction of metals and supports on the hydrodeoxygenation of phe cNOV a1573-15830 v793 a

Hydrodeoxygenation (HDO) is an important process for removing oxygen from lignin-derived phenolic monomers to obtain chemicals that can be used as fuel or fuel additives. A systematic study is performed to check the effects of supports (acidic, neutral, basic) and noble metals (Pd, Pt, Ru) on the HDO of phenol, guaiacol, and eugenol. Evaluation of the combinations of metals and supports under the similar reaction conditions shows that the metals supported on a highly acidic support (SiO2-Al2O3) yield complete hydrogenation products with the possibility of C[BOND]O bond cleavage to achieve a real HDO activity, whereas on a mildly acidic support (gamma-Al2O3), a complicated product distribution is achieved, and neutral (C) and basic (HT) supports give restricted hydrogenation activity but yield the products with very high selectivity. On the basis of the results, reaction pathways are suggested and deliberated. The catalysts show reproducible activity in recycle runs. The catalysts are characterized by various techniques (XRD, TEM, TPD, ICP-OES) to establish the catalyst activityproperty relationship.

1 aDeepa, Ayillath, K.1 aDhepe, Paresh, L. uhttp://library.ncl.res.in/content/function-metals-and-supports-hydrodeoxygenation-phenolic-compounds01287nas a2200157 4500008004100000022001400041245008700055210006900142260011000211300001600321490000600337520062000343100002400963700002900987856011301016 2014 eng d a2046-206900aSolid acid catalyzed depolymerization of lignin into value added aromatic monomers0 aSolid acid catalyzed depolymerization of lignin into value added aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcFEB a12625-126290 v43 a

Depolymerization of lignin to produce value-added aromatic monomers has attracted a lot of attention since these monomers can potentially be used as fuel additives (octane enhancers) and in turn can improve the prospects of cellulosic ethanol technology to become economically feasible. Here we show that solid acid catalysts could efficiently convert lignin into value added aromatic monomers with 60% yields and ca. 95% mass balance when depolymerization reactions were carried out at 250 degrees C for 30-120 minutes. We found that the reaction parameters have a remarkable effect on improving the yields.

1 aDeepa, Ayillath, K.1 aDhepe, Paresh, Laxmikant uhttp://library.ncl.res.in/content/solid-acid-catalyzed-depolymerization-lignin-value-added-aromatic-monomers02355nas a2200253 4500008004100000022001400041245011800055210006900173260010100242300001200343490000800355520142000363653002201783653001201805653001101817653001801828653001101846653002401857100002301881700002401904700002001928700002901948856012401977 2014 eng d a0974-362600aValue addition to lignocellulosics and biomass-derived sugars: an insight into solid acid-based catalytic methods0 aValue addition to lignocellulosics and biomassderived sugars an  aC V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIAbCatalysis Soc IndiacMAR a373-3850 v1263 a

For the synthesis of important platform chemicals such as sugars (xylose and arabinose) and furans (furfural and 5-hydroxymethylfurfural (HMF)) from carbohydrates (hemicellulose and fructose) solid acid catalysts are employed. Similarly, over solid acid catalysts, conversion of lignin into aromatic monomers is performed. It is observed that in the dehydration of fructose, because of higher hydrothermal stability, silicoaluminophosphate (SAPO) catalysts give better activity (78% HMF yield) compared with other solid acid catalysts (<63% HMF yield) at 175 degrees C. Particularly, SAPO-44 catalyst can be reused at least 5 times with marginal decrease in the activity. Zeolite, BUSY (Si/Al = 15) is active in the conversion of isolated (pure) hemicellulose to produce 41% C-5 sugars in water. The catalyst is also active in the selective conversion of hemicellulose from bagasse to yield 59% C-5 sugars. It is possible to obtain high yields of furfural (54%) directly from bagasse if instead of water, Water+toluene solvent system is used. Depolymerization of lignin using HUSY catalyst produced aromatic monomers with 60% yield at 250 degrees C. A detailed catalyst characterization study is performed to understand the correlation between catalyst activity and morphology. To understand the effect of impurities present in the substrate over solid acid catalysts, metal-exchange study is carried out.

10aaromatic monomers10aBiomass10afurans10aHemicellulose10alignin10asolid acid catalyst1 aBhaumik, Prasenjit1 aDeepa, Ayillath, K.1 aKane, Tanushree1 aDhepe, Paresh, Laxmikant uhttp://library.ncl.res.in/content/value-addition-lignocellulosics-and-biomass-derived-sugars-insight-solid-acid-based-002641nas a2200229 4500008004100000022001400041245007700055210006900132260007100201300001200272490000600284520184300290653002202133653001202155653002602167653002102193653001102214653002502225100002402250700002902274856010802303 2015 eng d a2155-543500aLignin depolymerization into aromatic monomers over solid acid catalysts0 aLignin depolymerization into aromatic monomers over solid acid c a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJAN a365-3790 v53 a

It is imperative to develop an efficient and environmentally benign pathway to valorize profusely available lignin, a component of nonedible lignocellulosic materials, into value-added aromatic monomers, which can be used as fuel additives and platform chemicals. To convert lignin, earlier studies used mineral bases (NaOH, CsOH) or supported metal catalysts (Pt, Ru, Pd, Ni on C, SiO2, Al2O3, etc.) under a hydrogen atmosphere, but these methods face several drawbacks such as corrosion, difficulty in catalyst recovery, sintering of metals, loss of activity, etc. Here we show that under an inert atmosphere various solid acid catalysts can efficiently convert six different types of lignins into value-added aromatic monomers. In particular, the SiO2Al2O3 catalyst gave exceptionally high yields of ca. 60% for organic solvent soluble extracted products with 95 +/- 10% mass balance in the depolymerization of dealkaline lignin, bagasse lignin, and ORG and EORG lignins at 250 degrees C within 30 min. GC, GC-MS, HPLC, LC-MS, and GPC analysis of organic solvent soluble extracted products confirmed the formation of aromatic monomers with ca. 90% selectivity. In the products, confirmation of retention of aromatic nature as present in lignin and the appearance of several functional groups has been carried out by FT-IR and H-1 and C-13 NMR studies. Further, isolation of major products by column chromatography was carried out to obtain aromatic monomers in pure form and their characterization by NMR is presented. A detailed characterization of six different types of lignins obtained from various sources helped in substantiating the catalytic results obtained in these reactions. A meticulous study on fresh and spent catalysts revealed that the amorphous catalysts are preferred to obtain reproducible catalytic results.

10aaromatic monomers10aBiomass10acolumn chromatography10adepolymerization10alignin10asolid acid catalysts1 aDeepa, Ayillath, K.1 aDhepe, Paresh, Laxmikant uhttp://library.ncl.res.in/content/lignin-depolymerization-aromatic-monomers-over-solid-acid-catalysts-0