Oxalate, Table

Results and Discussion The values of the above-mentioned parameters and the compositions of the primary products, found from their comparison, are listed in Table 16.64. The discrepancies between the calculated and experimental values of AyH do not exceed 5% for Ag, Ni, and Mn oxalates and 10% for Hg and Pb oxalates. For the latter two reactants, the discrepancies are most likely due to underestimation of the initial parameter E. This is confirmed by the overestimated experimental values of the Tm/E ratio for these oxalates (Table 16.63). When determining the optimal composition of the primary gaseous products, the similarity of the decomposition schemes for the reactions yielding similar solid products (metals or oxides) was taken into account. The most unexpected result was that the primary gaseous products contained, instead of equilibrium CO2 molecules, a mixture of CO and 02 molecules for Ag, Ni, Mn, and Pb oxalates and a mixture of CO and O for Hg oxalate. The corresponding differences in the enthalpies are 283 and 532 kJ moP, respectively, exceeding by an order of magnitude the possible measurement and calculation errors. 

Effects similar to those shown In Tables VII and VIII are obsei ed for the adsorption of lead upon preformed precipitates as Indicated by ThB adsorption upon preformed silver Iodide (Table IX) and silver oxalate (Table X). 

To find a suitable masking agent, we look for a species that binds with the interferent but does not bind with the analyte. Oxalate, for example, is an inappropriate choice because it binds with both Al and Fe. From Table 7.6 we find that thioglycolic acid is a selective masking agent for Fe in the presence of Al and that F is a selective masking agent for Al in the presence of Fe. 

Inorganic Analysis The most important precipitants for inorganic cations are chromate, the halides, hydroxide, oxalate, sulfate, sulfide, and phosphate. A summary of selected methods, grouped by precipitant, is shown in Table 8.1. Many inorganic anions can be determined using the same reactions by reversing the analyte... 

Table 1. Physical and Thermochemical Properties of Oxalic Acid and its Dihydrate...

Anhydrous Oxalic Acid. The anhydrous form of oxaUc acid is odorless and colorless. It exists in two crystal forms, ie, the rhombic or a-form and the monoclinic or P-form (3). The rhombic crystal is thermodynamically stable at room temperature, but the monoclinic form is metastable or slightly stable. The main difference between the rhombic and monoclinic forms exists in the melting points which are 189.5 and 182°C, respectively (Table 1)-... 

Table 2. Specific Gravities of Various Aqueous Solutions of Oxalic Acid Dihydrate...

Table 4. Supply and Demand of Oxalic Acid in tbe World Market in 1992, tons...

Uses of oxalic acid ia each region are summarized in Table 5 (58). The demand for agrochemical/pharmaceutical production and for separation/recovery of rare-earth elements in each region has been increasing. The use for marble polishing in western Europe is unique to the region. 

Calcium Oxalate. The monohydrate [5794-28-5], CaC2 04-H2 0, mol wt 128.10,is of importance principally as an intermediate in oxahc acid manufacture and in analytical chemistry it is the form in which calcium is frequentiy quantitatively isolated. Its solubihty in water is very low, lower than that of the other aLkahne-earth oxalates. The approximate solubihties of this and several related salts are indicated in Table 6. 

ROOC—COOH, are not. The dialkyl esters are characterized by good solvent properties and serve as starting materials in the synthesis of many organic compounds, such as pharmaceuticals, agrochemicals, and fine chemicals (qv). Among the diesters, dimethyl, diethyl, and di- -butyl oxalates are industrially important. Their physical properties are given in Table 7. 

Table 1. Effect of Temperature of Decomposition of the Product of Reaction of Pentafluorophenyllithium with Dimethyl Oxalate on Product Distribution [JJ]...

The austenitic irons are also useful in some circumstances for handling organic acids such as dilute acetic, formic and oxalic acids, fatty acids and tar acids. They are more resistant to organic acids than unalloyed cast irons, e.g. in acetic acid the austenitic irons show corrosion rates 20-40 times lower than the ferritic iron (Table 3.51). 

Table 9 includes data on the first dissociation constants of seven weak acids it will be recalled that we expect these to fall into class III. The table includes the second dissociation constants of five acids, phosphoric, sulfuric, oxalic, malonic, and carbonic, which fall into class IV, while the amino acids glycine and alanine provide four examples that should fall into class II. 

Table 9 contains six values of K lying between 10-6 and 10-4. One of these (oxalic acid) belongs to class IV, three belong to class III, and the remaining two arc the values of Kb just discussed. The fact that these six values of K lie between 10-4 and 10 means that the values of J do not differ by more than 20 per cent. Since J — (Jnm + J,i), a given value of J may arise from moderate values of / and J,i, or from a larger value of / combined with a smaller J,t, or from a smaller. / ... 

Comparison of Ca3(POi)2, Ca(C204), and Mg3(P04)2. The effects of cation and anion composites were tested by comparing the dissolution of Ca3(P04)2, Ca(C204), andMg3(P04)2 at pH 7 (Table 10). The dissolution of Ca3(P04)2 is achieved more effectively with X than with EDTA. However, when the anion is oxalate, the dissolution of Ca2+ is drastically reduced with X. EDTA can dissolve Ga(C204) to the same extent as Ca3(P04)2, i.e. the anion effect is insignificant. A better separation of Ca2+ from oxalate anion may be achieved by EDTA. 

Dissolution of Human Urinary Calculi in Vitro. Five human urinary calculi containing various proportions of Ca3(P04)2, Ca(C204), CaC03, and MgNH4(P04) were subjected to similar dissolution tests at pH 7 (Table 11). The same dissolution patterns as those of the model phosphate and oxalate calculi are found. That is, for phosphate calculi no. 1-4, X is more effective than [18]aneN6 or EDTA and for oxalate calculus no. 5, EDTA is best. 

As expected, similar treatment of 3-nitroarenes furnishes mixtures of 4- and 6-substituted 3H-azepines, 54 and 55, respectively.176 Comparable yields of mixed azepines were also obtained by deoxygenation of 3-nitroarenes with alkylphophorous triamides, formed in situ from hexa-methylphosphorous triamide and excess of a secondary amine.66 In a few cases the 3//-azepines were separated by fractional crystallization of their oxalate salts66 but, in general, pure isomers were not isolated and the yields cited in the table were determined by HNMR spectroscopy. 

Assumed tto be similar to that of other esters (like dimethyl oxalate) in Table 1. Assumed to equal that of O,. ... 

The requirements of the US Armed Forces are detailed in Mil Spec MIL-S-12210A, Strontium Oxalate , (11 Sept 1952) Strontium oxalate shall be of the following grades as specified Grade A — anhydrous strontium oxalate Grade B — hydrated strontium oxalate, and shall conform to the physical and chemical properties listed in Table 1... 

Conceptual Flowsheet for the Extraction of Actinides from HLLW. Figure 5 shows a conceptual flowsheet for the extraction of all the actinides (U, Np, Pu, Am, and Cm) from HLLW using 0.4 M 0< >D[IB]CMP0 in DEB. The CMPO compound was selected for this process because of the high D m values attainable with a small concentration of extractant and because of the absence of macro-concentrations of uranyl ion. Distribution ratios relevant to the flowsheet are shown in previous tables, IV, V, VI, and VII and figures 1 and 2. One of the key features of the flowsheet is that plutonium is extracted from the feed solution and stripped from the organic phase without the addition of any nitric acid or use of ferrous sulfamate. However, oxalic acid is added to complex Zr and Mo (see Table IV). The presence of oxalic acid reduces any Np(VI) to Np(IV) (15). The presence of ferrous ion, which is... 

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