Results 181 to 190 of about 18,959 (224)
Some of the next articles are maybe not open access.
Acid Catalysis by Heteropoly Acids
ChemInform, 2003The achievements in the field of acid catalysis by heteropoly acids having different structures HxPW11LO40 (L = ZrIV, TiIV, ThIV), HxZW12O40 (Z = SiIV, PV, BIII, CoIII, GeIV), H21B3W39O132, H6P2W18O62, H6P2W21O71, H6As2W21O69 are reviewed. The data on the acidity of HPAs are generalized. The rules of homogeneous and heterogeneous acid catalysis by HPAs
openaire +1 more source
Acids: Natural Acids and Acidulants
2003Acids, or acidulants as they are also called, are commonly used in food processing as flavor intensifiers, preservatives, buffers, meat-curing agents, viscosity modifiers, and leavening agents. This article discusses the functions that acidulants have in food systems and reviews the more commonly used food acidulants.
openaire +1 more source
Journal of Chemical & Engineering Data, 2004
Vapor pressure data were measured for the following carboxylic acids: propionic, butyric, isobutyric, valeric, isovaleric, hexanoic, and heptanoic acids. The pressure ranged between ∼5 kPa and atmospheric pressure (at sea level), and the corresponding temperatures were between 85 and 180 °C, depending on the acid being measured.
Scott L. Clifford +2 more
openaire +1 more source
Vapor pressure data were measured for the following carboxylic acids: propionic, butyric, isobutyric, valeric, isovaleric, hexanoic, and heptanoic acids. The pressure ranged between ∼5 kPa and atmospheric pressure (at sea level), and the corresponding temperatures were between 85 and 180 °C, depending on the acid being measured.
Scott L. Clifford +2 more
openaire +1 more source
The Second Acidic Constant of Salicylic Acid
Annali di Chimica, 2005AbstractThe second dissociation constant of salicylic acid (H2L) has been determined, at 25 °C, in NaCl ionic media by UV spectrophotometric measurements. The investigated ionic strength values were 0.16, 0.25, 0.50, 1.0, 2.0 and 3.0 M. The protolysis constants calculated at the different ionic strengths yielded, with the Specific Interaction Theory ...
PORTO R, DE TOMMASO G, FURIA, Emilia
openaire +3 more sources
Proton Acids, Lewis Acids, Hard Acids, Soft Acids and Superacids
1975Although the terms acid and base have been in use since the early days of chemistry, the meaning of these terms has undergone considerable modification through the centuries and continues even today with the recent introduction of new terms such as hard acid, soft acid and superacid.
openaire +1 more source
Derivatives of Dehydroquinic Acid, Dehydroshikimic Acid, Shikimic Acid, and Chorismic Acid
1984Dehydroquinic acid, shikimic acid, and chorismic acid are carboxylated compounds containing a six-membered carbocyclic ring with one or two double bonds (Fig. 143). The secondary products derived from these substances either still contain the ring and the C1-side chain of the acids (see the structure of the benzoic acid derivatives, of anthranilic and ...
openaire +1 more source