Fixed phenolic acids

For our soils water, EDTA, citrate, NaOH, etc. extractions were carried out on individual samples or subsamples of soils with or without amendment phenolic acid(s). Thus the recovery for each extractant comprised the sum of the free , reversibly sorbed, and/or fixed (not immediately available to roots or microbes) phenolic acids that were recoverable by a given extractant. Differences between water extractions (primarily free phenolic acids) and EDTA or citrate ( free and reversibly sorbed phenolic acids) extractions were utilized to estimate reversibly sorbed phenolic acids. Differences between EDTA or citrate extractions and NaOH extractions were utilized to estimate the fraction of fixed phenolic acids that could be recovered by NaOH. For additional details see Section 2.4.3. This approach has been criticized because free phenolic acids were not removed from soil samples before reversibly sorbed phenolic acids were extracted (Ohno and First 1998). However, in a preliminary study extracting our soils by the traditional method (removing free ... 

Water-autoclave extractions were also much more efficient than neutral EDTA extractions in recovering sorbed/fixed phenolic acids from plant tissues/residues (Blum et al. 1992). For example HPLC analysis of EDTA extracts for wheat stubble collected after a wheat harvest contained no detectable phenolic acid peaks. Water-autoclave extracts of this wheat stubble had 11 distinct peaks. Concentrations for ferulic acid, vanillic acid, p-coumaric acid, and p-hydroxybenzoic acid were 33, 22, 1034, and 47 p,g/g dry weight, respectively (Fig. 3.8). On the other hand water and... 

There is a substantial literature on the transformation of simple phenolic acids by microorganisms.2,7,11,16,18,20,22,25,29,44 For example, ferulic acid is transformed by fungi to either caffeic acid or vanillic acid, and these are transformed to protocatechuic acid. Next the ring structure of protocatechuic acid is broken to produce 3-carboxy-c/s,c/s-muconic acid, which is then converted to (3-oxoadipic acid (Fig. 3.1), which in turn is broken down to acetic acid and succinic acid, and these ultimately are broken down to C02 and water.11,18,29 Flowever, distribution of residual 14C-activity after growth of Hendersonula toruloidea, a fungus, in the presence of specifically 14C-labeled ferulic acid ranged from 32 to 45% in C02, 34 to 45% in cells, 9 to 20% in humic acid and 4 to 10% in fulvic acid.29 Thus, a considerable portion of the ferulic-acid carbon was bound/fixed over a 12-week period, and the initial ferulic acid transformation products (e.g., caffeic acid, vanillic acid and protocatechuic acid) were clearly of a transitory nature. Similar observations have also been made for other simple phenolic acids 22,23 however, the proportions metabolized to C02 and fixed into cells and the soil... 

Fixative for acid dyes on nylon or wool. Very low free phenol/formaldehyde content. Effective reserve for direct dyes in nylon/cellulosic dyeing. 

As said above, plant root chemistry may also influence deeply alpine soil microorganism s biomass. It turns out that the particular chemical composition of exudates is a strong selective force in favour of bacteria that can catabolize particular compounds. Plants support heterotrophic microorganisms by way of rhizodeposition of root exudates and litter from dead tissue that include phenolic acids, flavonoids, terpenoids, carbohydrates, hydroxamic acids, aminoacids, denatured protein from dying root cells, CO2, and ethylene (Wardle, 1992). In certain plants, as much as 20-30% of fixed carbon may be lost as rhizodeposition (Lynch and Whipps, 1990). Most of these compounds enter the soil nutrient cycle by way of the soil microbiota, giving rise to competition between the myriad species living there, from microarthropods and nematodes to mycorrhiza and bacteria, for these resources (e.g. Hoover and Crossley, 1995). There is evidence that root phenolic exudates are metabolized preferentially by some soil microbes, while the same compounds are toxic to others. Phenolic acids usually occur in small concentration in soil chiefly because of soil metabolism while adsorption in clay and other soil particles plays a minor role (Bliun et al., 1999). However, their phytotoxicity is compounded by synergism between particular mixtures (Blum, 1996). 

To separate neutral phenolics from phenolic acids in wine [190] and apple juice [179-180], an extraction with ethyl acetate at fixed pH values of seven and two has been proposed. Extraction efficiencies determined with standard solutions of (+)-catechin, (-)-epicatechin and procyanidin... 

Rates of phenolic acid sorption (reversible and irreversibly sorbed or fixed) to sterile soils varied over time. Immediately after addition of phenolic acids to soils (first 1-4 h) there was a very rapid sorption (primarily irreversible sorption) for both the cinnamic acid and benzoic acid derivatives (Figs. 2.15 and 2.18 Blum et al. 

Phenolic acids in soils occur either in a free state in the soil solution, reversibly sorbed to soil particles, fixed (irreversibly sorbed) very tightly to soil particles (e.g., recalcitrant organic matter, and clays), and/or on and in living and dead plant tissues/residues ( free , reversibly sorbed, and fixed). Of general interest to plant-plant allelopathic interactions are the free and reversibly sorbed states frequently referred to as the available fraction. Of particular interest is the active fraction of available phenolic acids, the fraction of available phenolic acids that actually interact with seeds, roots and microbes. Unfortunately we presently do not have a means of quantifying the active fraction, thus the focus on the available fraction. 

Types of thin layers. The phenolic acids arising from clinical studies (88) have been examined by TLC on cellulose (88-90) and with cellulose on Silufol (91). TLC was considered superior to paper chromatography. The identification of phenolic acids in varieties of Ribes nigrum has been described (IS), and separation of phenolic acids fix>m plant material or silica gel G and quantitative analysis with spectrophotometry (92). Phenolic acids extracted from plants were best separated on silica gel G with chloroform-ethyl acetate-formic acid (5 4 1) (8). TLC on silica gel combined with scanning spectrophotometry was used to separate nine phenolic acids in wine with hexane-ethyl acetate-formic acid (15 9 2) (93) as the preferred of the 10 solvents examined. Twenty naturally occurring phenolic acids were separated by a combination of one- and two-dimensional TLC and development with three solvents (94) and phenolic acids (and some phenols) related to humic acid examined on alumina with water as solvent (94a). Silica gel F-254 (Silica-Rapid-Platten Woelm in... 

Among continuous reactors, the dominant system used to produce parasubstituted alkylphenols is a fixed-bed reactor holding a soHd acid catalyst. Figure 3 shows an example of this type of reactor. The phenol and alkene are premixed and heated or cooled to the desired feed temperature. This mix is fed to the reactor where it contacts the porous soHd, acid-impregnated catalyst. A key design consideration for this type of reactor is the removal of the heat of reaction. 

A process for the production of DPA from phenol and ammonia has been reported (25). Typically, the reaction is carried out continuously ia a fixed-bed reactor usiag an acidic alumiaa catalyst at 300°C—420°C. The first product formed is aniline which is subsequently converted to DPA. Consequently, the reaction can be carried out to simultaneously produce DPA and aniline, ia any desired ratio, simply by varyiag the molar ratios of phenol (and aniline) ia the reactor feed stream. 

The procedure of simultaneous extracting-spectrophotometric determination of nitrophenols in wastewater is proposed on the example of the analysis of mixtures of mono-, di-, and trinitrophenols. The procedure consists of extraction concentrating in an acid medium, and sequential back-extractions under various pH. Such procedures give possibility for isolation o-, m-, p-nitrophenols, a-, P-, y-dinitrophenols and trinitrophenol in separate groups. Simultaneous determination is carried out by summary light-absorption of nitrophenol-ions. The error of determination concentrations on maximum contaminant level in natural waters doesn t exceed 10%. The peculiarities of application of the sequential extractions under fixed pH were studied on the example of mixture of simplest phenols (phenol, o-, m-, />-cresols). The procedure of their determination is based on the extraction to carbon tetrachloride, subsequent back-extraction and spectrophotometric measurement of interaction products with diazo-p-nitroaniline. 

U.S. consumption pattern 1999, 3 619t U.S. producers, 3 610t vapor-phase nitration of, 17 257 vinyl chloride reactions with, 25 632 world production by country, 3 611-612t Benzene-based catalyst technology, 15 500 Benzene-based fixed-bed process technology, 15 505-506 Benzene chlorination process, of phenol manufacture, 18 751 m-Benzenedisulfonic acid, 3 602 p-Benzenedisulfonic acid, 3 602 Benzene feedstock, 23 329 Benzene hexachloride, 3 602 Benzene manufacture, toluene in, 25 180-181... 

It must further be mentioned that the acylation of alcohols, phenols, and amines with acid chlorides (and also anhydrides) is now frequently carried out in pyridine solution instead of according to the older Schotten-Baumann method (action of acid chloride in aqueous-alkaline suspension). The hydrogen chloride is fixed by the pyridine. 

Phenol, 4-4-vinyl Fr fixed oipE° Phenylacetic acid, para-hydroxy Fr Ju E074 Phenylethanol, 3-4-dihydroxy Fr°E05i Phenylethanol, 4-hydroxy, glucoside Fr E034 Phenyl-glycol, 3-4-dihydroxy Fr EOSl Phytoene Fr fixed oiP ... 

Phenolic There are various kinds of phenolic resins. The ones that are produced from phenol-formaldehyde condensation are veiy weak acid exchangers, where the phenolic -OH groups are the fixed-ionic groups. The formaldehyde content decides the extent of cross-linking in the resin. On the other hand, phenolsulfonic acid resins contain both strong acid -S03H and weak acid -OH groups. 

---