Additives lignin derived

This process can provide some advantages fi>r ethanol production, compared with acid hydrolysis process because of the extremely it >id reaction, ratha small and simple plant may be designed without use of add catalyst hi addition, lignin-derived products are not contaminated as in sulfuric acid lignin in the add hydrolysis process, so that th can be appropriate to be convated into the value-added aromatic products. Thus, the ovaall process would lead to the effidait utilization of the whole lignocellulosics. 

In addition to the normally suggested, sample pre-treatment procedures used prior to l.c. injection to avoid column contamination, Cig bonded silica-gel cartridges are particularly useful for removal of lignin-derived degradation-products that occur in biomass-conversion samples. 

Methods. A typical hydrogen peroxide bleaching operation consists of treatment of a 20% HPL solution in 60-75% aqueous ethanol with 25-50% hydrogen peroxide (by weight) on lignin derivative at 80°C. The reaction medium is adjusted to pH 2 by the addition of HC1, or to pH >12-13 by NaOH. Color loss is determined by UV/VIS absorbance measurements on suitably diluted samples. 

We now wish to report our results on isolating lignin-derived dimers by alkaline hydrogenation and to propose mechanisms for their formation. In addition, we will present some information on the (NMR) spectra of these and related compounds this technique has been useful for analyzing the structure of lignin degradation products and related synthetic materials. 

Figure 4 Variations in of total OC (left axis %o, open circles) and the abundance of lignin-derived syringyl and vanillyl phenols (right axis A, mg per 100 mg OC, triangles) in surface sediments from various water depths of the Gulf of Mexico in the vicinity of the outflow from the Mississippi River system (after Goni et aL, 1997 Also shown are average values for the same parameters determined on suspended particulate matter from the upper and lower reaches of the Mississippi River (extreme left column, error bars = 1 SD data from Onstad et ai, 2000). In addition, values are indicated for one lignin phenol (syringic acid filled circles), for selected shelf and slope...

Biomass resources will become more important in the future as alternative chemicals and fuel from fossil resources. Such alternatives can be carbon-neutral and renewable. Therefore, the use of biomass is of benefit for our global environments. The present study has clearly demonstrated a potential of woody biomass resources to be converted into useful chemicals in supercritical water. In addition, the products derived from cellulose and hemicelluloses were effectively separated from lignin-derived products. This raises the possibility of converting whole biomass substrates to alternative chemicals, and provides ample opportunities for human beings to produce useful biomass-based products as chemicals and bio-fuels W ithout using fossil resources... 

Structural information gained from thioacidolysis of permethylated samples is provided by a routine technique. In contrast, the last development of thioacidolysis, the analysis of lignin-derived dimers after an additional desulfurization step, is not an easy technique to master. 

The pathways of carbon flow in eukaryotes are more complex than in prokaryotes, mainly because the C2 units produced within mitochondria can be exported (e.g. for lipid biosynthesis) only as part of a citrate unit produced in the citric acid cycle. The branch point in carbon flow to either isoprene or acetate can lead to additional isotopic fractionation. In general, it seems that n-alkyl hpids in a particular organism are depleted in 13C by c. 1.5%o relative to isoprenoids produced from the same substrate (Hayes 1993). In higher plants, the phenolic precursors of lignin derive from glucose (Fig. 2.29), so it is not surprising that the carbon isotopic composition of lignin reflects the major photosynthetic pathway involved (C3 or C4 Benner et al. 1987). 

A typical Py-GC-MS trace from a wood sample (Figure 9) contains 50-100 individual peaks corresponding to at least that many products. The individual pyrolysis products include fiirans plus a variety of carbonyl compounds that are typical of polysaccharides, particularly cellulose and hemi-cellulose (42). In addition, many different lignin-derived phenols are obtained that, like the CuO reaction products, retain the methoxylation pattern of the parent structural units and carry diagenetic information on their side chains (43). Characteristic pyrolysis products of wood extractives such as resin acids also can be detected (44) thus, this analytical method is... 

The need to keep metal surfaces clean led to the development of additives called antifoulants and dispersants. Many natural organics such as tannins and lignin derivatives have been used as dispersants. As an... 

It can be concluded that kraft pulping in particular offers attractive possibilities to manufacture alternative bioproducts in addition to the traditional market of pulp and extractives (turpentine and tall oil). However, the specific utilization of various hemicellulose- and lignin-derived fractions for chemical and fuel purposes is complex, and their manufacturing depends on several factors, such as the type of feedstock, available conversion technologies, production scale, energy and pulp prices, as well as pollution problems. For example, besides a straightforward combustion of... 

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