Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Compositional table

Direct Oranges. AU principal commercially produced direct oranges are of disazo or stUbene chemical composition (Table 5). Direct Orange 102 (65) (R = COO Na+ ), is manufactured by first coupling aniline to 6,6 -ureylenebis-l-naphthol-3-sulfonic acid foUowed by a second coupling with /)-aminobenzoic acid [150-13-0]. 6,6 -Ureylenebis-l-naphthol-3-sulfonic acid [134-47-4] is the coupling component in many of the most important direct colors. It is produced by phosgenation of two moles of J-acid (6-ainino-l-naphthol-3-sulfonic acid). [Pg.440]

Direct Reds. The principal commercially produced direct reds, with revealed chemistry, are of disazo or polyazo composition (Table 6). Direct Red 81 (68) is manufactured by couplingp- -aminopheny1azo)henzenesu1fonic acid to A/-benzoyl J-acid Other important direct red dyes iaclude those shown ia Figure 5. [Pg.441]

For copolymers of acrylamide with sodium acrylate, the preexponential factor K and exponent a of [tj] = KM depend on copolymer composition (Table 3). [Pg.63]

A similar situation is observed when studying the effect of temperature on inhibition of thermal destruction of polyethylene by fiber glass of varying composition (Table 6). The molecular weight of polyethylene is practically unchanged when exposed over a period of 6 hours at 350°C with 30% of fiber glass containing 16%... [Pg.84]

Thermal stability is a crucial factor when polysaccharides are used as reinforcing agents because they suffer from inferior thermal properties compared to inorganic fillers. However, thermogravimetric analysis (TGA) of biocomposites suggested that the degradation temperatures of biocomposites are in close proximity with those of carbon black composites (Table-1). [Pg.122]

As illustrated in Fig. 1, the activated carbon displays the highest conversion and selectivity among all the catalysts during the initial reaction period, however, its catalytic activity continues to decrease during the reaction, which is probably caused by coke deposition in the micropores. By contrast, the reaction over the CNF composites treated in air and HN03 can reach a pseudo-steady state after about 200 min. Similiar transient state is also observed on the CNFs and the untreated composite. Table 3 collects the kinetic results after 300 min on stream over catalysts tested for the ODE, in which the activity is referred to the BET surface area. The air-treated composite gives the highest conversion and styrene selectivity at steady state. [Pg.723]

Despite the ubiquitous distribution of chlorophylls in all photosynthetic plants, quantitative information exists only for a few vegetables. The most common edible plants lack definitive data and consequently no information is available about chlorophyll distribution in current food composition tables. Still more difficult is to find analytical data in literature about the individual amounts of chlorophyll a and b and their respective derivatives. [Pg.195]

In this phase of the risk assessment, the validity and reliability of conclusions and advice to risk managers depend on the quality, reliability, and relevance of available exposure data. Therefore it is necessary to (1) critically review the facts from food composition tables and the reasons for differences reported by and within countries, (2) consider the way foods are categorized and thus made comparable (or not) in food consumption surveys, and (3) explore how to refine assessments as more information becomes available. ... [Pg.569]

Fractions were pooled as indicated in the figure and analyzed for their sugar compositions (Table 3). The sugar compositions clearly show that most of the neutral sugars were concentrated in the large fragments that eluted close to the void volume of the column (Fraction... [Pg.84]

Imidazole-HCl soluble polysaccharides Most of the polysaccharides of this group didn t elute from the Q-Sepharose column with 10 mM buffer (Table 3). The glycosyl composition (Table 4) shows that these polysaccharides are homogalacturonans and ramnogalacturonans with... [Pg.572]

Characteristics of fraction I. The carbohydrate content of Fraction I was 84.4 %, in which the main component is D-galacturonic acid (71 %). Consequently, the polysaccharide is of a pectic type. The neutral sugars accounted for 13.4 % and according to their qualitative composition (Table 2) they correspond to the composition of pectin, isolated from sunflower heads (18). It is worth noting the high content of L-arabinose and D-galactose, compared with the other monosaccharides. The protein content was 7.8 %. [Pg.683]

A special type of homogeneous measurements is found in a compositiorml table which describes chemical samples by means of the relative concentrations of their components. By definition, relative concentrations in each row of a compositional table add up to unity or to 100%. Such a table is said to be closed with respect to the rows. In general, closure of a table results when their rows or columns add up to a constant value. This operation is only applicable to homogeneous tables. Yet another type of homogeneous table arises when the rows or columns can be ordered according to a physical parameter, such as in a table of spectroscopic absorptions by chemical samples obtained at different wavelengths. [Pg.87]

Multivariate analysis of these different types of measurements (heterogeneous, homogeneous, compositional, ordered) may require special approaches for each of them. For example, compositional tables that are closed with respect to the rows, require a different type of analysis than heterogeneous tables where the columns are defined with different units. The basic approach of principal components... [Pg.87]

Lipoproteins. A lipoprotein is an endogenous macromolecule consisting of an inner apolar core of cholesteryl esters and triglycerides surrounded by a monolayer of phospholipid embedded with cholesterol and apoproteins. The functions of lipoproteins are to transport lipids and to mediate lipid metabolism. There are four main types of lipoproteins (classified based on their flotation rates in salt solutions) chylomicrons, very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL). These differ in size, molecular weight, and density and have different lipid, protein, and apoprotein compositions (Table 11). The apoproteins are important determinants in the metabolism of lipoproteins—they serve as ligands for lipoprotein receptors and as mediators in lipoproteins interconversion by enzymes. [Pg.557]

Many dyes that have no chemical affinity to fibrous substrates can be attached to such substrates by intermediary (go-between) substances known as mordants. These are either inorganic or organic substances that react chemically with the fibers as well as with the dyes and thus link the dyes to the fibers. Mordants are traditionally classified into two main classes, acid and metallic mordants. The acid mordants are organic substances that contain tannins (see Textbox 64) as for example, gall nuts and sumac. The metallic mordants are inorganic substances, mostly mineral oxides and salts that include metal atoms in their composition. Table 94 lists mordants of both these types, which have been used since antiquity. [Pg.392]

In case of Cu-Dy composites (Table 11.1) dysprosium concentration is higher in sonicated condition in comparison to normal condition, whereas, in case of Mn-Dy... [Pg.305]

P. Cok, B. De Bernard, M.P. Radillo, F. Francescato, Synoptic Food Composition Tables, Edizioni Piccini, Padova, 1986. [Pg.28]

The consumption of flavonoids in different populations is variable, and in many cases the amount is underestimated because calculations are derived from the analysis of few foods or because of the lack of proper food composition tables in the countries (Sarria, 2004 Nijvelt and others 2001). Chun and others (2007) estimated the consumption of flavonoids by adults in the US as 189.7 mg/day. This value was much higher than those reported by other authors for the same population as well as for other countries such as Denmark (23 16 mg/day), Finland (3.4-24 mg/day), Netherlands (23 mg/day), and Japan (63 mg/day)(Chun and others 2007). Johannot and Somerset (2006) estimated the ingestion of flavonoids for an Australian population (n = 13,858) at around 351 mg/day. They found that tea was typically the main source of flavonoids. Although it was observed that the types of flavonoids and their sources varied according to age, these authors noted that it is necessary to carry out more research with more consistent methodologies to validate the ingestion of specific flavonoids and to facilitate the international comparison. [Pg.158]


See other pages where Compositional table is mentioned: [Pg.141]    [Pg.284]    [Pg.281]    [Pg.133]    [Pg.76]    [Pg.69]    [Pg.188]    [Pg.152]    [Pg.1157]    [Pg.396]    [Pg.808]    [Pg.418]    [Pg.1046]    [Pg.31]    [Pg.178]    [Pg.190]    [Pg.136]    [Pg.430]    [Pg.86]    [Pg.515]    [Pg.570]    [Pg.89]    [Pg.294]    [Pg.403]    [Pg.187]    [Pg.205]    [Pg.203]    [Pg.5]    [Pg.300]    [Pg.792]    [Pg.418]    [Pg.173]   
See also in sourсe #XX -- [ Pg.87 ]




SEARCH



© 2024 chempedia.info