Alkoxy Phenols Research Articles

Catalytic cracking of Etek lignin with zirconia supported metal-oxides for alkyl and alkoxy phenols recovery

Alkyl and alkoxy phenols are desirable products from the catalytic depolymerisation of lignin. In this work, ex-situ catalytic pyrolysis of Etek lignin in presence of Na, Ce, NiCe, MgCe, Fe and FePd on ZrO2 was studied. The largest combined yield of monomeric phenolics and alkylphenols was produced by Na/ZrO2 catalysts. A parametric study of the most promising Na/ZrO2 then resulted in using a catalyst:lignin ratio of 3:1 at 500 °C as the best option, enhancing at 17.5 wt% the recovery of total phenolics including 6 wt% alkyl phenols, which is equivalent to 27.8 wt% and 9.5 wt% of the starting lignin in Etek lignin waste. The study of the catalyst basicity indicates that the mild basicity of Na/ZrO2 was mostly responsible for the enhanced mono phenols recovery. Due to formation of thermally stable Na2CO3 during pyrolysis, successful Na/ZrO2 regeneration requires temperature of 900 °C or higher.

Pyrolytic characteristics of hemicellulose, cellulose and lignin under CO2 atmosphere

To understand the influence of CO2 on biomass pyrolysis, the pyrolysis behavior of hemicellulose, cellulose, and lignin with CO2 were investigated by thermogravimetric analysis and a fixed-bed reactor. The detailed formation behavior of the pyrolysis products (chars, liquids, and non-condensable gases) was monitored and characterized to determine the role of CO2. The char and liquid yield of the three components were higher under CO2 than under N2 below 650 °C. For hemicellulose, more C elements were released as CO (from 1.25 mol% to 10.56 mol%) but the char yield decreased from 22.00 wt% to 10.50 wt% at 750 °C and the yield of ketones and furans was reduced. For cellulose, the yield of levoglucosans, furans, and ketones increased, but the yield of CO decreased (from 3.98 mol% to 3.10 mol% at 750 °C). For lignin, the selectivity of alkoxy phenols (G/S) increased whereas simple phenols decreased with more O elements released as CO (from 1.70 mol% to 3.41 mol% at 750 °C). For solid char, all samples exhibited more CO and COO groups with CO2 at 750 °C.

Engineering the Catalytic Properties of HZSM5 by Cobalt Modification and Post-synthetic Hierarchical Porosity Development

Hierarchical zeolites have been identified as special catalytic materials with improved catalytic properties. In this study, hierarchical bifunctional ZSM5 based catalysts were prepared by desilication for controlled mesoporosity development and have been modified by Co doping. Their performance in the catalytic pyrolysis of oak in a lab scale reactor was evaluated. Desilicated counterparts were proven more active in deoxygenation of bio oil, while carbon deposition on the catalysts reduced compared to non-desilicated counterparts. Increased Lewis acidity favors decarboxylation reactions, while higher olefins as well as PAH content indicate easier diffusion within and from the porous network and interactions in the mesopores. The conversion of bulky lignin molecules (alkoxy phenols) is enhanced by the mesopores, while acidity is of secondary importance. Coke deposition inside the pores is more profound in the desilicated catalysts due to larger pore size. Carbon deposition on the catalysts is reduced in the following order: HZSM5 > Co/HZSM5 > Ds-HZSM5 > Co/Ds-HZSM5. GC–MS characterization of the CH2Cl2 soluble coke indicated that for the desilicated counterparts the main coke precursors are the bulky lignin molecules which are partially deoxygenated.

Low temperature microwave-assisted pyrolysis of wood sawdust for phenolic rich compounds: Kinetics and dielectric properties analysis

Microwave-assisted pyrolysis of wood sawdust for phenolic rich compounds was carried out between 400 and 550°C in a batch reactor. An efficient preparation of liquid products was observed at 500°C with a yield of 58.50%, which was similar to conventional fast pyrolysis. The highest concentration of phenolic compounds in liquid product reached up to 78.7% (area) in which the alkoxy phenols contributed 81.8% at 500°C. Microwave thermogravimetric analysis using KAS method was used firstly to investigate the low-temperature pyrolytic behaviors and activation energy. The results indicated that effective pyrolytic range was 250–400°C and average activation energy was 42.78kJ/mol, which were 50–100°C and 50–100kJ/mol lower than conventional pyrolysis, respectively. Analysis on dielectric properties of pyrolytic products confirmed that accelerated pyrolysis and low temperature were attributed to the formation of instantaneous “hot spots”.

Catalytic pyrolysis of corn straw fermentation residue for producing alkyl phenols

Phenolic-oil can be upgraded by etherification with methanol to decrease the polarity and acidity of the product oil. However, alkoxy phenols have an inhibiting effect to the etherification of alkyl phenols in the phenolic mixture. So, it is very important to produce alkyl phenols with high selectivity and extremely low content of alkoxy phenols, through a catalytic pyrolytic process. Herein, the effects of HZSM-5, NaY, and KH2PO4/AA (KH2PO4 loaded on activated Al2O3) on the pyrolysis of corn straw fermentation residue are investigated, for producing alkyl phenols high efficiently. KH2PO4/AA is found to be the best catalyst in promoting the formation of alkyl phenols and in inhibiting alkoxy phenols. Under the catalysis of KH2PO4/AA, the tar yield increases with rising temperature, and reaches to the maximum tar yield of 13.7% at 500 °C, and then declines with further increasing temperature. The tar obtained under optimized reaction conditions, nearly consists of 50% of alkyl phenols and over 23% of aliphatic hydrocarbons with zero content of alkoxy phenols. K3Al2(PO4)3 is generated from the solid phase reaction between KH2PO4 and Al2O3, through which alkoxy phenols can be high selectively adsorbed and activated, and thus leads to the formation of alkyl phenols.

Influence of HSAPO-34, HZSM-5, and NaY on pyrolysis of corn straw fermentation residue via Py-GC/MS

The lignin-rich biomass materials can widely be obtained from the resources of black liquor and lignocellulose fermentation residue. The reutilization of the waste lignin-rich biomass material relates to environment, energy, and materials, and thus worth for investigation with great enthusiasm. In this paper, the pyrolysis of corn straw fermentation residue (CSFR) under catalysis of three zeolites of HSAPO-34, HZSM-5, and NaY zeolite were investigated via the instrument of Py-GC/MS. The results showed that the main pyrolytic products were alkoxy phenols, alkoxy aromatics, 2,3-dihydro-benzofuran, alkyl phenols, and alkyl aromatics. Additionally, some acids, long-chain hydrocarbons, and saccharides were also identified. Comparatively alkyl aromatics could be more generated under the catalysis of HZSM-5, while NaY zeolite promoted the formation of phenol more distinctly. HSAPO-34 exerted a weakest influence to all product components with close similarities to the non-catalytic curves. The different catalytic behaviors of the three zeolites could be attributed to their different acidities and textural structures.

Catalytic Upgrading of Phenolic Oil by Etherification with Methanol

AbstractCatalytic etherification of phenolic oil with methanol was investigated to decrease the polarity and acidity of the product oil. The catalyst KH2PO4/activated alumina (AA) provided the best performance due to its excellent dehydration and anti‐coking property. When catalyzed by KH2PO4‐AA, the content of aryl ethers increased with rising temperature during the early stage but decreased at 500 °C. Alkoxy phenols had an inhibiting effect on etherification of alkyl phenols due to adsorption competition. Aryl ethers were mostly generated from alkyl phenols, while alkoxy phenols also contributed by simultaneous conversion to dialkoxybenzenes and diphenols, with a higher selectivity to diphenols. This explained the reduced alkoxy phenols and more generated alkyl phenols and aryl ethers at 350 °C.

A structure-activity correlation for the antibacterial action of a series of m-alkoxy phenols against Escherichia coli

A structure-activity correlation for the antibacterial action of a series of <i>m</i>-alkoxy phenols against <i>Escherichia coli</i>

Enthalpies of solution of a series of m-alkoxy phenols in water, n-octanol and water-n-octanol mutually saturated: derivation of the thermodynamic parameters for solute transfer between these solvents.

Enthalpies of solution in both water and n-octanol have been determined for a series of phenols, in a microcalorimeter modified for titration. The thermodynamic data for solution in n-octanol and in water, as well as for transfer between the two, have been calculated from the free energies of transfer, based upon partition coefficients, and the free energies of solution, based upon solubility data. The results are discussed in terms of solute-solvent interactions in both phases and are used to assess, critically, the use of n-octanol as lipid-like solvent in QSAR studies.

Solution thermodynamics for alkoxy phenols in alcohol and in water-alcohol systems

Solubilities have been measured for m-alkoxyphenols in water-alcohol mixtures. The alcohols ranged from the co-solvent methanol to the co-solute 1-octanol, and each alcohol was present at the saturating concentration of 1-octanol in water viz. 0.00316M. Plots of sobubility vs. carbon number of the alcohols show discontinuities. Enthalpies of solution in these same solvent systems have also been measured. The enthalpies of solution and the derived enthalpies of transfer both support the observations on solubilities. The results are discussed on the basis of solvent-solute interactions and in terms of solute volumes.

ChemInform Abstract: OXIDATION OF ALKOXY PHENOLS. XXIV. A DIPHENO‐2,2′‐QUINONE FROM SESAMOL

Chemischer InformationsdienstVolume 9, Issue 44 Preparative Organic Chemistry ChemInform Abstract: OXIDATION OF ALKOXY PHENOLS. XXIV. A DIPHENO-2,2′-QUINONE FROM SESAMOL F. R. HEWGILL, F. R. HEWGILLSearch for more papers by this author F. R. HEWGILL, F. R. HEWGILLSearch for more papers by this author First published: October 31, 1978 https://doi.org/10.1002/chin.197844104Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume9, Issue44October 31, 1978 RelatedInformation