Acidic groups, compounds with

Compounds with a smaller/C., and larger pKa are less acidic, whereas compounds with a larger/Ca and smaller plsimple alcohols like methanol and ethanol are about as acidic as water but substituent groups can have a significant effect, tert-Butyl alcohol is a weaker acid, for instance, and 2,2,2-trifluoroethanol is stronger. Phenols and thiols, the sulfur analogs of alcohols, are substantially more acidic than water. 

The main characteristics of FAB-MS are indicated in Table 6.15. FAB ionisation is relatively simple to perform. However, parameter optimisation and data interpretation of the resulting FAB spectra can be complex. Matrix selection for additive analysis is crucial. Solubility of the additives in the matrix is essential for production of viable spectra. FAB/FIB is well suited to organic compounds which exhibit some polarity, and contain either acidic and/or basic functional groups. Compounds with basic groups run well in positive ionisation mode, and those with acidic centres run well in the negative ionisation... 

On-line FTIR spectra of the pigment fractions suggested that each pigment contains both hydroxyl and carboxyle groups and they are tannic acid-like compounds with high molecular mass [313],... 

Boronic acid-agarose Compounds with c/s-diol groups sugars, catecholamines, ribonucleotides, glycoproteins... 

Acidities of / -Dicarbonyl Compounds Table 22-1 compares the acidities of some carbonyl compounds with the acidities of alcohols and water. Notice the large increase in acidity for compounds with two carbonyl groups beta to each other. The a protons of the jS-dicarbonyl compounds are more acidic than the hydroxyl protons of water and alcohols. This enhanced acidity results from increased stability of the enolate ion. The negative charge is delocalized over two carbonyl groups rather than just one, as shown by the resonance forms for the enolate ion of diethyl malonate (also called malonic ester). 

The second main class of acids are compounds with X—OH groups of the type H XOm, for example, H3P04, or better 0=P(0H)3. 

Organic acids—Organic compounds with the general formula RC-OH, where R is a hydrocarbon group. 

Two pKa values are reported for malonic acid, a compound with two CCX)H groups. Explain why one pKg is lower and one pKg... 

Manufacture of hydroxyphosphonic acids from compounds with C=0 groups and phosphorous acid... 

Starting with the benzyl-imidazole (compound 1), which binds to angiotensin II (All) receptor but exhibits a very poor potency, Duncia et supposed that a second acidic group (compound 2) would provide, at physiological... 

Since fluorine-containing organic compounds are more acidic than the hydrocarbon analogs, we started to study benzylic compounds that have trifluoromethyl groups and chlorine atoms to increase their acidity. Two compounds with rates of protodetritiation similar to that for 9-PhFl-9-t were of interest QH5CH(CF3)2 1 and P-CF3QH4CHCICF3 [P-CF3-2]. Measurement of the pfQ values for 1 and P-CF3-2 are not possible in solution due to elimination of a y9-fluoride. However, Mishima has been able to obtained their gas phase acidities, AG =... 

Kramer et al. reported in 1974 on a new biologically active phosphoric acid ester group. Compounds with herbicidal activity can be characterised with the following general formula ... 

Carbonic acid—a compound with two OH groups bonded to the carbonyl carbon— is unstable, readily breaking down to CO2 and H2O. The reaction is reversible, so carbonic acid is formed when CO2 is bubbled into water (Section 1.20). 

The polymer may be modified with functional or reactive groups in a reactor or an extruder, via reactive extrusion. Polyolefin modified with maleic anhydride, acrylic acid, glycidyl methacrylate, acid groups neutralized with a metal cation (ionomer), itaconic acid, or anhydride or similar compounds have been widely reported as compatibilizers because these groups have the ability to form a chemical linkage or a polar or ionic interaction with polar polymers such as polyamides (PAs), polyesters, and others. 

Major final degradation products excreted into urine are generally extensively oxidised, e.g. tetranor dicarboxylic acids [262,269,272,274]. The further metabohsm of the initially formed 15-keto-13,14-dihydroprostaglandins thus involves one or two steps of /8-oxidation, wl- or w2-oxidation to col- or co2-hydroxyl, col-aldehyde or CO 2-ketone and, in the former case, also co-carboxylic groups. Compounds with the co-carboxylic group can be /8-oxidised also from the co-end. 

Figure 5.2 Rhubarb and spinach contain oxalic acid, a compound with two carboxyl groups. The nomenclature of di-carboxylic acids is not discussed here. What would you propose as the lUPAC ending for molecules with two carboxyl groups ...

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