Sodium carbonate alkalizer

The most intensive bleaching action is achieved with paste bleaches, which are prepared before use by mixing hydrogen peroxide solution (6-12 vol%) with a bleach powder. The powder consists of a peroxodisulfate, an alkalizing agent, stabilizers, thickeners, and other additives. Sodium, potassium, or ammonium peroxodisulfate is used. The ammonium salt is most effective when combined with an alkalizing component such as sodium carbonate or silicate, ammonia is formed. 

The mixture of 1.4 kg o-nitrophenol, 2.1 kg o-aminophenol, 6 kg glycerine (d = 1.26) and 5 kg sulfuric acid (d = 1.848) was heated at reflux to temperature 130°-140°C. This temperature was kept for 1.5 hours. The obtained oxyquinoline precipitated, the liquid was removed with water-steam distillation. The residue was diluted with water and alkalized with sodium hydroxide and sodium carbonate to the strong alkaline reaction. The repeated distillation with water steam gave the oil, which hardened as the long needles by cooling. MP 75°-76°C recrystallized from diluted ethanol. 

There is a striking difference, however, in the action of various alkaline materials. Neutralizing acid paper with sodium carbonate, as is shown later, prolongs its life. Alkalizing paper to pH 10 with sodium carbonate causes paper to darken, to oxidize, and to degrade. The effects are most pronounced in humid-oven accelerated aging, less so in the dry-oven aging. 

The present research therefore has two aims, the first to show that paper alkalized with a sodium compound—sodium carbonate—behaves in the presence of a transition metal catalyst in the manner indicated by the literature. The second aim is to learn to what extent the behavior of paper alkalized with the alkaline earth compounds differs from this. 

From the previous discussion, when paper is alkalized to pH 10 with sodium carbonate, it should show an increase in the rate of degrada-... 

Figures 5 and 5A and Table V show the results when the paper at pH 9.9 was alkalized with sodium carbonate. It maintained reasonable folding strength in the dry oven, and not much acid was produced by the...

Several alkalization agents have been developed as possible alternatives to sodium bicarbonate. These include carbicarb (a mixture of sodium carbonate and sodium bicarbonate) and tris-hydroxymethylaminomethane (also called THAM or tromethamine). These agents theoretically produce a lesser increase in plasma carbon dioxide tension and, therefore, less CSF and intracellular acidosis. However, this does not appear to be the case for tromethamine, which resulted in a decrease in CSF pH similar to sodium bicarbonate in healthy horses (Pedrick et al 1998). 

The slurry is filtered by suction and the filter cake washed with 50 ml. of water at room temperature. To the filtrate warmed to 35° and strongly agitated, about 65 g. of sodium carbonate is added in 1- to 2-g. portions. The temperature is brought up to 45°. The slurry is tested a few minutes after each addition with blue litmus paper. When a distinct, permanent but mildly alkaline condition is reached (red litmus changing to a pale, not a deep, blue), the addition of sodium carbonate is stopped. The warm slurry is filtered and the cake washed with 150 ml. of water at 50° made alkaline to litmus with sodium carbonate. The precipitate is sucked as dry as possible. The filter cake is slurried in 200 ml. of water, made slightly alkaline to litmus with sodium carbonate, and the slurry, heated to 45°, is filtered and washed with 50 ml. of shghtly alkalized water at 50°. If the combined filtrates do not react slightly alkaline to litmus, a httle more sodium carbonate is added and the solution refiltered. 

Sodium, potassium and calcium salts of mono and polyphosphoric acids, incl. such salts when alkalized with sodium carbonate, sodium hydroxide or sodium silicate... 

When the carbonated front reaches sufficient depth, the steel reinforcement corrodes due to loss of passivity. The process of re-alkalization is, therefore, employed to recreate the alkaline conditions on the reinforcement by attracting Ca " ions and Na+ ions (see below) which keeps it in a passive state. The vicinity of reinforcement is re-alkalized and a new passive layer is thus regenerated. The re-alkalization process is a consequence of the electrochemical chloride removal process. The anodes used are the same as the one used for chloride removal (titanium or steel). Sodium carbonate is used as an electrolyte. The function of Na2C03 is to introduce alkali metal ions from an external source, however it would not be necessary to use Na2C03 if alkali reactive a egates are present in the concrete in which case water is used as an electrolyte. The introduction of alkaline metal ions prevents the occurrence of re-carbonation. At the anode oxidation takes place according to... 

Electrochemical re-alkalization This is an electrochemical process which introduces hydroxyl ions and alkaline metal ions in the concrete cover from an external source of electrolyte, such as sodium carbonate. This process reverses re-carbonation. The steel reinforcement is made the negative electrode which attracts cations such as Ca" " and Na if present. Freeze-thaw cycle As the temperature of the hardened concrete is lowered, the water in the capillary pores in the cement phase freezes. On thawing, not all expansion is lost and on freezing further expansion takes place so that freeze-thaw cycle has a cumulative effect. Hardened concrete The strength achieved by concrete upon hardening. 

Procedure A drop of the nitroprusside solution to which acetaldehyde has been added (one tenth of the volume of the nitroprusside solution) is added to a drop of the aqueous amine solution and the mixture is alkalized with sodium carbonate solution. A blue to violet color is immediately formed. 

A variety of adverse effects have been reported following the use of antacids. If sodium bicarbonate is absorbed, it can cause systemic alkalization and sodium overload. Calcium carbonate may induce hypercalcemia and a rebound increase in gastric secretion secondary to the elevation in circulating calcium levels. Magnesium hydroxide may produce osmotic diarrhea, and the excessive absorption of Mg++ in patients with renal failure may result in central nervous system toxicity. Aluminum hydroxide is associated with constipation serum phosphate levels also may become depressed because of phosphate binding within the gut. The use of antacids in general may interfere with the absorption of a number of antibiotics and other medications. 

Currently, most cocoa powders are produced by the so-called Dutch or alkalized process, in which the nib is treated with a warm aqueous solution of up to three parts of anhydrous potassium carbonate to 100 parts of nib (or equivalent amounts of other alkalis such as potassium bicarbonate and hydroxide carbonates, bicarbonates, and hydroxides of sodium, magnesium, and ammonium or their combinations). After the alkali is completely absorbed, the nib is processed as in the above method to yield alkalized cocoa powder. Alkalized cocoa is considered to have improved dispersibility, color, and flavor over unalkalized cocoa. 

It is well known, and shown in potential-pH diagrams, that an alkalization of the corrosive medium has a beneficial effect on the corrosion resistance of some metals, notably ferrous metals. Cyclohexylamine and dicyclohexylamine are moderately strong bases (pZa = 10.66 and 11.25, respectively). The pH of the solutions of their salts with weak acids will depend on the pi a of the acid. For example, cyclohexylamine carbonate will have a rather alkaline pH (pZa for carbonic acid 6.37), whereas dicyclohexyl ammonium nitrite will have a neutral pH (pFCa = 3.37 for nitrous acid). Guanidine is a strong base (pZa = 13.54) and is mainly used as an additive in VCI formulations to adjust the alkalinity. Buffers (sodium tetraborate, etc.) may have to be used to maintain the pH of a VCI formulation at a convenient level. 

Selective etherification of the 3-hydroxy group of 1,3-dihydroxy-lO-methyl-acridone (19) with excess bromoacetaldehyde diethylacetal in dry dimethylformamide, either by use of sodium hydride at 120"C in a bomb, or in the presence of potassium carbonate at 100°C under nitrogen, afforded 3-(2,2-diethoxyethoxy)- -hydroxy-10-methylacridone (314). Cyclodehydration of 314 by refluxing in a mixture of dioxane and dilute aqueous sulfuric acid, followed by alkalization by addition of sodium hydroxide and heating, gave the desired furacridone (26), accompanied by smaller amounts of the linear isomer, isofuracridone (315) 330). 

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