The X-ray structure of a sodium peroxide hydrate, Na2O2•8H2O, and its reactions with carbon dioxide: relevance to the brightening of mechanical pulps

The main component of the solid originally believed to be a peroxosilicate with pulp-brightening properties has been shown to be Na2O2•8H2O. The solid crystallizes in the monoclinic space group C2/c, with an empirical formula H8O5Na, and with a = 14.335(3), b = 6.461(1), c = 11.432(2) Å, β = 118.28(3)°, and Z = 8. The centrosymmetric structure consists of a peroxide anion with an O—O distance of 1.499(2) Å. Each of these oxygen atoms is at the apex of an approximate square-based pyramid, the base of which consists of four oxygen atoms of water molecules. The bases of the two pyramids are staggered when viewed down the peroxide bond. Each sodium is at the centre of an approximate octahedron of water molecules, four of which bridge other sodium atoms and two bridge to the peroxide anions. One hydrogen atom of each of these two water molecules is terminal and the other two are hydrogen bonded to peroxide oxygen atoms. The compound reacts very rapidly with CO2 in moist air to form Na2CO3, but in drier conditions, formation of the carbonate can take many days and proceeds via a percarbonate, believed to be Na2CO4. This has been identified by infrared spectroscopy and X-ray powder diffraction and can persist for long periods in dry air. Key words: sodium peroxide hydrate, sodium percarbonate, pulp brightening, X-ray diffraction, infrared.

Sulfonyl esters 3. The formation of sulfone-sulfonates in the reactions of aryl methanesulfonates with sodium hydride

Sodium hydride reductions of aryl methanesulfonates afford dimeric sulfone-sulfonate esters as well as products arising from SO bond rupture. SO bond rupture becomes more competitive as the LUMO energy of the sulfonate ester declines. Exploration of the chemistry of a sulfone-sulfonate ester revealed a complex novel reaction that resulted in the formation of, inter alia, a dichloromethanesulfonate ester and a trichloromethanesulfonate ester. The first successful approaches to the synthesis of the heretofore unknown trichloromethanesulfonates and dichloromethanesulfonates are reported. Key words: sodium hydride reductions, sulfenes, sulfone-sulfonate esters

EFFECTS OF FEEDING SODIUM BICARBONATE TO PREPARTUM DAIRY COWS ON THEIR PERFORMANCE IN EARLY LACTATION

Forty cows of second or greater parity were selected and blocked into 20 groups of two and randomly assigned to one of two prepartum diets; control prepartum (CP) or buffer prepartum (BP). The prepartum ration consisted of 85% grass hay, 10% ground corn and 5% dry cow supplement (dry basis). Sodium bicarbonate (NaHCO3) was fed at 0.6% of the total dry matter (DM) in the BP group. The postpartum ration was formulated to meet requirements for high-producing dairy cows in early lactation. Dry cows were placed on prepartum treatments 3 wk prior to expected calving date and abruptly switched to the postpartum ration on day 4 after parturition. For the first 4 wk of lactation the average daily total and concentrate DM intake as a percentage of body weight (BW) for cows fed rations BP and CP were not different. Forage intake as a percentage of BW and average production of 4% fat-corrected milk (FCM) was greater for CP than for BP. Milk fat test for CP and BP was not different. No differences were observed between CP and BP for rumen fluid parameters measured on days 14, 7 and 3 ± 2 prepartum. Total VFA (mg dL−1) and ratio of acetate-to-propionate was greater for CP than for BP; butyrate as a percentage of total VFA was greater for BP than for CP. Compared to controls, cows fed NaHCO3 prepartum did not perform as well during the first 4 wk postpartum as indicated by their lower forage intake and 4% FCM production. Key words: Sodium bicarbonate, cows (dairy), prepartum, performance

HIGH LEVELS OF SODIUM CHLORIDE IN SUPPLEMENTS FOR GROWING CATTLE

Two trials were conducted to evaluate the effects of high levels of sodium chloride in energy and (or) protein supplements on performance and digestive and metabolic parameters of growing beef cattle. In each trial, 24 Hereford steers averaging 196 kg initial weight were individually fed corn silage or fescue hay plus an energy and (or) protein supplement containing NaCl. Consumption of the low (LS) and high (HS) levels of NaCl was 22–23 g d−1 and 192–193 g d−1, respectively. In Trial 1 the high NaCl supplement tended to reduce gains and feed efficiency of steers fed silage whereas gains were similar for those fed low and high NaCl and fescue hay. In Trial 2, gains and feed efficiencies were similar for both NaCl treatments. Rumen fluid total volatile fatty acid concentrations were lower (P < 0.05) at day 70 of both trials with high NaCl. Steers fed high NaCl had lower rumen ammonia concentrations at days 56 and 70 of Trial 1, while no significant differences were noted at day 70 of Trial 2. Molar percentages of valeric acid were reduced at each sampling with high NaCl diets. Serum Na levels were similar for the two NaCl levels, whereas K levels were increased at day 70 due to high NaCl. Rumen liquid digesta flow rates were increased (P < 0.05) in animals fed the high NaCl supplements, whereas total solid digesta and soybean meal rate of passage were not affected by NaCl level in the supplement. Supplements containing high levels of NaCl do induce changes in rumen function but do not consistently affect animal performance. Key words: Sodium chloride, supplements, beef cattle, corn silage, fescue hay

RELEASE OF AVAILABLE SULFUR FROM FERTILIZERS

The rate of release of plant-available sulfur (S) from two soluble sources (thiosulfate, and sulfate) and four elemental S forms (S powder, S-coated urea, S suspension, and S-impregnated urea) was determined in a growth chamber study, using five successive harvests of rapeseed as the test crop. The soluble S sources were plant-available shortly after application. Thiosulfate was rapidly oxidized, and was comparable to sulfate in its short-term release pattern. The elemental S forms, however, showed widely different rates of release, apparently related to the initial particle size of the product and the dispersion of the particles within the soil. Finely-divided S suspension was rapidly oxidized, and the product was completely converted to sulfate by the third harvest. Relatively coarse S powder was oxidized more slowly and in some cases was not completely converted to sulfate even after 124 days. S-impregnated urea, which yields a pocket of finely divided S particles upon urea dissolution, showed negligible initial oxidation but rapid oxidation after the soil was mixed. S-coated urea produced minimal amounts of sulfate over the five harvests and could not be considered a viable fertilizer S source. Key words: Sodium sulfate, sodium thiosulfate, S-coated urea, S-impregnated urea, S oxidation, elemental S

GROWTH AND METABOLIC PARAMETERS IN STEERS FED HIGH LEVELS OF SODIUM CHLORIDE AND LIMESTONE

Sixty-four yearling steers were fed a fattening diet plus 0.5% NaCl (control), 2% limestone, 5% NaCl, or 5% NaCl plus 2% limestone. Feeding 5% NaCl and 5% NaCl plus 2% limestone resulted in decreased total gain (P < 0.01), average daily gain (P < 0.01) and carcass weight (P < 0.05) while 5% NaCl decreased the efficiency of organic matter utilization (P < 0.05). Sodium chloride supplementation decreased ruminal pH and acetate to propionate ratio at day 62 but there was no effect of NaCl evident in samples collected on day 118. Blood glucose was decreased (P < 0.05) at days 62 and 118 in steers fed 5% NaCl and 5% NaCl plus 2% limestone. Supplementation with high levels of sodium chloride nonsignificantly increased the percentage of starch in cecal and colon digesta samples collected at slaughter. Also the NaCl treatment decreased pH (P < 0.05) in the colon and acetate to propionate ratio (P < 0.10) in the cecum. Although NaCl supplementation altered ruminal and digestive parameters, it did not result in increased performance. Key words: Sodium chloride, limestone, beef cattle, growth

EFFECT OF SODIUM BICARBONATE ON RUMEN TURNOVER IN FREQUENTLY FED SHEEP

In four rumen-cannulated sheep fed 0, 1.5, 3.0 and 4.5% NaHCO3, the buffer increased rumen pH (P < 0.01) and isobutyrate (P < 0.10) but not rumen ammonia, lactate or other volatile fatty acids. Water intake increased (P < 0.01), liquid turnover rate varied quadratically (P < 0.09) and solids retention time and rumen solids volume varied cubically (P < 0.09 and P < 0.01) with NaHCO3 levels. Key words: Sodium bicarbonate, liquid turnover rate, solids retention time, sheep