Study of Aromatic Compounds Derived from Sugarcane Bagasse. Part I: Effect of pH

This work aims at increasing the knowledge about the recovery of aromatic compounds from the lignin fraction of sugarcane bagasse, as well as exploring the possibility to recover these fine chemicals of great concern for many industrial sectors. The major natural products contained in the lignin fraction of such a straw material were extracted in previous work by alkaline hydrolysis using different concentrations of NaOH and amounts of bagasse, and HPLC analyses revealed that the extracts mainly contained p‐coumaric acid, ferulic acid, syringic acid, and vanillin, the first three containing and the last lacking a carboxyl group. All these aromatic compounds have well‐known antioxidant power and are very important in pharmacology. For these reasons, they have been investigated in this study by UV spectrophotometry, with special concern to the pH effect on their spectra and determination of their pK_a values.     

Removal of Cu (II) from water pollutant with Tunisian activated lignin prepared by phosphoric acid activation

Activated lignin with a relative high BET surface area and a well-developed porosity has been prepared from Tunisian deposit lignin, by H₃PO₄ activation at various process conditions. Physical and chemical properties of activated carbons produced, implying BET surface area, Boehm titration, Fourier Transform Infrared Spectroscopy (FTIR) and thermogravimetric analysis (TGA), were investigated. It was found that the maximum surface area reached at the carbonization temperature of 500 °C in H₃PO₄ activation, and that the activated lignin prepared from lignin acidic activation, showed a surface area of 463 m²/g. The potential application of these carbons for the removal of heavy metal contaminant, has been investigated by measuring their adsorption capacities for Cu (II) as representative of main local toxic contaminant found in industrial wastewaters. The results obtained compare well and even favourably with those reported in literature for other unconventional materials.     

SODIUM LIGNIN SULFONATE TO STABILIZE HEAVY CRUDE OIL-IN-WATER EMULSIONS FOR PIPELINE TRANSPORTATION

ABSTRACT

The efficiency of sodium lignin sulfonate (SLS) as an anionic surfactant derived from waste wood pulping industry in stabilizing an Egyptian heavy crude oil (Geisum)-in-water emulsions for pipeline transportation has been investigated. The stability and rheology of the emulsions stabilized by SLS or with a nonionic surfactant nonyl phenol diethylenetriamine formaldehyde ethoxylate (NDFE) individually or in a mixture have been studied. It has been found that the dynamic shear viscosity of the crude oil decreases substantially when it is emulsified with water in the form of an oil-in-water type of emulsion. The stability of the oil-in-water emulsion increases as the surfactant concentration increases. Potable water and saline water containing different molar concentrations of NaCI have been used to study the effect of aqueous phase salinity on the stability and viscosity of the emulsion. Surfactant dissolved in saline water has been utilized to find out the possibility of injecting the surfactant into a well bore to effect emulsification in the pump or tubing for enhancing the production of heavy crude oils as oil-in-water emulsion. The study revealed that, the viscosity of the emulsion containing potable water is always less than that containing saline water and the viscosity increases as the salt content increased.     

Synthesis and properties of lignin-highly branched poly (ester-amine) polymeric systems

Combined characteristics of hydrogen bonded/cross-linked polymer networks based on lignin motifs have been developed. This new type of polymeric material was prepared from an industrial lignin and a highly branched poly(ester-amine) (HBPEA) obtained by melt polycondensation of 1,1,1-triethanolamine (TEA) and adipic acid (AA). The lignin-HBPEA polymers were shown to be insoluble in common organic solvents and were characterized by FTIR and NMR spectroscopies. Thermo-mechanical measurements showed that melt mixing HBPEA with 40% lignin results in a flexible and tough material (T_g; 7.7 °C and E′ 3.5 GPa). The hydrogen bonding recognition was based on various hydroxyl groups in lignin and aliphatic ester groups from HBPEA. The extent of interactions could be controlled by varying the amount of lignin added. These networks were thermally reversible and have highly tunable mechanical properties that were controlled by the extent of interactions. High level of mechanical properties could be achieved through the addition of lignin-poly(ester-amine) covalent cross-links. This study shows that the poly(ester-amine) structure plays an important role in the thermo-mechanical properties. By varying the spacer length between lignin and tertiary amine unit, materials with various thermo-mechanical properties were also obtained from the same parent polymer backbone.     

Products properties from fast pyrolysis of enzymatic/mild acidolysis lignin

The conversion of enzymatic/mild acidolysis lignin (EMAL) isolated from moso bamboo to aromatic chemicals by fast pyrolysis were investigated under nitrogen atmosphere and atmospheric pressure. The experiment of EMAL pyrolyzing was set on a tubular reactor furnace at the temperature levels of 400, 500, 600, 700, 800 and 900 °C, and the products derived from EMAL pyrolyzing were classified into three-phase of gas, condensed liquid (tar), and solid (char). The chemical structure and surface morphology of solid product were characterized by fourier transforms infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), and the ingredients of gas product and liquid (tar) were analyzed with gas chromatography (GC) and gas chromatography/mass spectrometer (GC/MS). The analysis results indicated that the yield of char decreased rapidly from 43% to 28% with an increase of temperature, and the yield of gas product increased gradually from 6% to 26%, and the yield of tar attained a maximum at 700 °C. SEM showed that char took on lots of vesicles that resulted from the gas release from EMAL pyrolyzing. The ingredients of gas product were comprised of H₂, CO, CO₂ and light hydrocarbons (CH₄, C₂H₄ and C₂H₆), and the amount of H₂, CO were high. Besides a huge amount of phenols, the tar contained aromatic hydrocarbons, chain hydrocarbons, monoaromatic aromatic hydrocarbons and some ketones, and the carbon number of chemical compounds were C₆–C₁₀.     

SODIUM LIGNIN SULFONATE TO STABILIZE HEAVY CRUDE OIL-IN-WATER EMULSIONS FOR PIPELINE TRANSPORTATION

The efficiency of sodium lignin sulfonate (SLS) as an anionic surfactant derived from waste wood pulping industry in stabilizing an Egyptian heavy crude oil (Geisum)-in-water emulsions for pipeline transportation has been investigated. The stability and rheology of the emulsions stabilized by SLS or with a nonionic surfactant nonyl phenol diethylenetriamine formaldehyde ethoxylate (NDFE) individually or in a mixture have been studied. It has been found that the dynamic shear viscosity of the crude oil decreases substantially when it is emulsified with water in the form of an oil-in-water type of emulsion. The stability of the oil-in-water emulsion increases as the surfactant concentration increases. Potable water and saline water containing different molar concentrations of NaCI have been used to study the effect of aqueous phase salinity on the stability and viscosity of the emulsion. Surfactant dissolved in saline water has been utilized to find out the possibility of injecting the surfactant into a well bore to effect emulsification in the pump or tubing for enhancing the production of heavy crude oils as oil-in-water emulsion. The study revealed that, the viscosity of the emulsion containing potable water is always less than that containing saline water and the viscosity increases as the salt content increased.     

The Present Status and Potential of Kraft Lignin-Phenol-Formaldehyde Wood Adhesives

Kraft lignin (KL), a phenolic polymer formed during the kraft pulping process, is presently burned as a low value fuel. For decades, researchers have attempted to use KL as an inexpensive substitute for phenol in phenol-formaldehyde (PF) resins, but no one has produced a commercially satisfactory KL-PF resin. This paper reviews the literature on the present status of KL-PF adhesives and makes recommendations on needed research.

Kraft lignin solutions are complex mixtures which have broad molecular weight distributions, high viscosities, relatively low reactivities, and low solubilities. Attempts to overcome these inherent problems include methylolation of lignin to improve reactivity, the use of co-solvents to improve solubility, and ultrafiltration to yield more homogeneous molecular weight fractions. Future research efforts need to focus on understanding the fundamental chemical and physical properties of kraft lignin and its resins. The search for an economic lignin-based wood adhesive should continue.     

碱木素阴离子型高分子絮凝剂的合成与应用

本文研究以碱木素为原料，通过交联反应和磺化反应，制备碱木素阴离子型高分子絮凝剂，它在有机高浓度蛋白质废水处理中的应用．试验结果表明．本絮凝剂具有良好的絮凝沉降效果．     

Polybutadiene-g-polypentafluorostyrene as a coupling agent for lignin-filled rubber compounds

This study investigated the role of polybutadiene-g-polypentafluorostyrene (PB-g-PPFS) as a coupling agent between lignin and styrene butadiene rubber (SBR) in preparation of compounds with higher mechanical strength and lower viscoelastic loss. Lignins are three-dimensional amorphous polymers consisting of benzene rings carrying alkyl, alkoxy, and hydroxyl groups as substituents. These substituents render lignin electron-rich. The PPFS domains in PB-g-PPFS provide an electron-deficient π-ring system that can couple lignin with rubber via arene–perfluoroarene interactions. PB-g-PPFS molecules were synthesized with 2:1 molar ratio of pentafluorostyrene and polybutadiene, respectively. The arene–perfluoroarene interactions were confirmed by UV–vis spectroscopy and the morphology was examined by scanning electron microscopy. The tensile strength improved by 20% and 10% for compounds of lignin and lignin–carbon black hybrid fillers, respectively. The loss tangent value reduced due to improved filler–rubber interactions promoted by PB-g-PPFS compounds.     

染料分散剂新原料-高沸醇木质素的研制

采用1，4-丁二醇水溶液为溶剂的高沸醇溶剂法，从松木，杉木，稻草等原料制备纤维素与高沸醇木质素。使用上述原料，在70%-90%1，4-丁二醇水溶液中添加少量催化剂。并在190℃-220℃条件下蒸煮1-3小时后，分离反应产物，得到固体纤维素与高沸醇木质素-丁二醇溶液，不溶于水的高沸醇木质素通过加水沉淀的方法。从反应后的液体混合物中分离。高沸醇木质素具有较高的反应活性。灰分含量很低。适于制备新型染料分散剂，有广泛应用前景。