Salts Of Weak Acids Research Articles

Corrosion of Steel in Dilute Solutions Of Sodium Salts of Weak Acids

Abstract It was found that the exposure of steel specimens to dilute solutions of common anodic inhibitors such as sodium carbonate, sodium silicate, disodium phosphate and trisodium phosphate, fre...

Acidimetric Titrations of Salts of Weak Acids. Equilibria in the Copper(II)—Mandelate System

Acidimetric Titrations of Salts of Weak Acids. Equilibria in the Copper(II)—Mandelate System

Effect of inhibitors on phosphate uptake in excised gills of the mussel (Mytilus edulis).

SummaryExcised fragments of gills of Mytilus edulis L., a pelecypod mollusk, were irrigated with artificial sea water containing P32. The rate of uptake of phosphate in the presence of 0.001 M inhibitors was compared with the control rate. Inhibition of phosphate uptake in the presence of cyanide, sulfide, and iodoacetate, and the lack of inhibition by azide and fluoride, are considered from the point of view of available knowledge of the penetration of such substances into cells. Cyanide and sulfide, being salts of weak acids, penetrate the cells and probably affect the turnover rate of intracellular phosphate. The lack of effect with fluoride is consistent with its existence in the completely dissociated state. Iodoacetate, also completely ionized, may be effective at the cell surface, affecting the permeability of the cell to phosphate. The apparent rise in the rate of phosphate uptake in the presence of cysteine remains unexplained.

Physicochemical investigation of a cation exchange resin (amberlite IR100) I. Resin equilibria

1. 1. Equilibria between a sulfonic acid resin (Amberlite IR100) and salts of strong and weak acids are investigated. The limiting exchange (at high concentrations) is nearly the same for all alkali and alkaline earth chlorides and sulfates at low pH. It is greater for salts of weak acids, at higher pH, and increases in the order of decreasing acid dissociation constant. This suggests that the resin contains groups which are more weakly acid than -S0 3H, probably -COOH and phenolic -OH. The limiting exchange at pH = 2.0–2.5 is a few per cent below the strong acid equivalent as characterized by the sulfur content and the potentiometric titration curves. 2. 2. The law of mass action is applied to resin equilibria with salts of strong acids. The ratio of activity coefficients of the hydrogen ion to that of metal ion in the resin phase shows a marked variation with the experimental conditions. A number of possible causes for this is discussed.

Effect of pH on the Activity of some Respiratory Inhibitors

CHANGES of pH have been shown to influence the activity of certain respiratory inhibitors, for example, iodoacetate1, azide2, fluoride3 and malonate4. We have been led to a detailed investigation of the effects of pH change on some of these inhibitors since they are all the salts of weak acids, and one of us (E. W. S.) has recently examined the influence of pH on the fungistatic action of weak acids allied to phenol5.

Interaction between cellulose nitrate in solution and inorganic salts

AbstractPartI. It was confirmed that certain cellulose nitrates in 1% solution in acetone become more viscous and finally gel on standing over CaO, PbO, the basic salts of weak acids and strong bases, and certain other materials. The gels, whose formation was facilitated by increased temperature, were broken by the addition of a small amount of acid. The rate of gelling increased with the nitrogen content of the cellulose nitrate, indicating that residual hydroxyl groups were not involved. Nor did gelling occur under the same conditions in 1% solutions of cellulose acetate and ethyl cellulose of comparable degree of substitution. The rate of gelling was enormously increased when COOH groups were artificially introduced into the cellulose before nitration. Gelation is most probably due, therefore, to the cross‐linking of different cellulose nitrate chains through COOH or possibly SO3H groups.Part II. Dilute (< 0.2%) cellulose nitrate solutions on standing over CaO show a fall in viscosity with time (contrast 1). By ultracentrifuge examination this was shown to be due (for CaO and PbO treated solutions), not to degradation of the cellulose nitrate chains, but to association processes leading to the formation of aggregates of higher sedimentation constant and molecular weight. Sedimentation constants corresponding to molecular weights of several millions were observed from a cellulose nitrate of initial molecular weight ca. 100,000. Untreated control solutions showed no change in the state of aggregation. The association processes followed an approximately first‐order law at room temperature and were made more rapid by increase in temperature. After sedimentation, the association products could not be redispersed. Calcium introduced into cellulose nitrate before solution in acetone did not cause association or any other noticeable effect at low concentration.

Estimation of some official salts of weak organic acids by titration in a nonaqueous medium

A study was made of the potentiometric titration of a number of official salts of weak organic acids, notably sodium benzoate, sodium acetate, sodium propionate, barbital sodium, phenobarbital sodium, sulfathiazole sodium and sulfadiazine sodium, using a solvent mixture of propylene glycol and isopropyl alcohol and perchloric acid in the same solvent as a titrant. The results were compared with results obtained by the empirical use of indicators. In some instances when the potentiometric end point, determined with a Fisher titrimeter, gave low results, the empirical use of methyl orange or methyl red gave satisfactory results.

Estimation of Salts of Weak Acids by Direct Titration in Mixed Solvent

Estimation of Salts of Weak Acids by Direct Titration in Mixed Solvent

A direct volumetric method for the analysis of soap

Glycol, or preferably its mixture with a solvent for hydrocarbons, such as isopropyl alcohol or chloroform, possesses high solvent power for soaps, which may be directly titrated with strong acids, either potentiometrically or with the use of methyl red or methyl orange. The ionization of the organic acid is suppressed so that salts of weak acids can be directly titrated by this method. The colors of the indicators are brighter and the end-point sharper than those in alcohol or water.

137. The elimination of chlorine from sodium chloroacetate by the salts of weak acids

137. The elimination of chlorine from sodium chloroacetate by the salts of weak acids

Colloid Chemistry of Clay Drilling Fluids

It is only within the past 10 years that serious attempt appears to havebeen made to improve rotary drilling fluids by the application of theprinciples of colloid chemistry, although the use of chemicals to control therheological properties of clay slips has long been known in the ceramicindustry. The main difficulty apparently lay in the lack of a complete analysisof all of the functions of a drilling fluid in the drilling of the well, together with the lack of adequate consideration of how colloid science couldbe applied to secure these ends, and particularly how apparent antitheticalproperties of the fluid could be compromised. Thus one analysis1 of the manyrequirements of a drilling fluid proved conclusively that the viscosity shouldbe low, in order that cuttings and entrained gas might be eliminatedefficiently in the settling ditch, while the loss in carrying capacityaccompanying low viscosity could be regained by increasing either the densityof the mud or the upward velocity of the mud stream in the annular space of thewell, and the danger of sticking of the drill stem due to rapid settling incase of enforced suspension of drilling operations could be eliminated byenhancing the thixotropic properties of the fluid. The desired properties of the drilling fluid having thus been established, itwas a natural step to treat the fluid with viscosity-reducing chemicals, suchas salts of weak organic acids- for example, sodium tannate or gallate-and toadjust the pH to the alkaline side to such a degree of thixotropy as would give low viscosityand low yield point under the conditions of flow prevailing in the settlingditch, but rapid gelation and high yield point when quiescent in the annularspace during shutdowns. In fact, flow in the settling ditch should be justshort of turbulent while flow in the well, together with the flow of mud pastthe cuttings, is practically always turbulent. The use of chemicals other thanthose mentioned, such as Calgon (sodium hexametaphosphate) and certain otherphosphates together with sodium tannate, has now become standard practice andit is the consensus that this method of treatment has proved to be an importantstep in the development of the art of drilling oil wells. It is safe to assume that the application of colloid chemical principles canalso help in solving other outstanding problems of drilling fluids, such as thedevelopment of cheaper and more efficient viscosity reducers; the developmentof chemicals that do not lose their effectiveness in a short time duringdrilling operations; the finding of chemicals to preserve the plasteringproperties of muds when concentrated brines are encountered or in drillingthrough salt beds; improvement in the plastering properties of poor muds byfurther deflocculation, and, conversely, the prevention of excessivedeflocculation of certain marine shales sometimes encountered; the preparationof muds suitable for the successful drilling of heaving shale formations; thefinding of chemicals to treat the mud to prevent or to diminish lostcirculation; T.P. 1201

Active Constituent of Local Anesthetic Solutions

Such local anesthetics as are salts of weak bases and strong acids—and most local anesthetics come under this chemical classification—have repeatedly been shown to be more effective, particularly f...

Solubilities of Weak Acids in Salts of Weak Acids at Very High Concentrations.

Solubilities of Weak Acids in Salts of Weak Acids at Very High Concentrations.

388. The dissociation constants of organic acids. Part VII. Acetic acid: a correction. The solvent correction for salts of weak monobasic acids

388. The dissociation constants of organic acids. Part VII. Acetic acid: a correction. The solvent correction for salts of weak monobasic acids

Some favorable effects from the alimentary administration of insulin.

Since July, 1922, when absorption of insulin from the alimentary tract was first observed by us, various attempts have been made to devise a practicable method for oral administration. No difficulty was experienced in demonstrating absorption of simple extracts by depancreatized dogs proving that insulin can survive the destructive action of the stomach. With normal animals, normal human subjects and diabetic patients having an efficient supply of trypsin the insulin was almost always destroyed., Nevertheless a few instances of obvious absorption were encountered in human diabetics. These were reported in brief at the 11th International Congress of Physiologists at Edinburgh, July, 1923. In this same month attempts were made to delay the destructive action of trypsin by combining with insulin certain weak organic acids and enclosing the combination in enteric coated capsules. Later enteric coated tablets were prepared for us by reputable pharmaceutical houses. Several cases have now been treated for different lengths of time with these tablets. Not all reacted favorably. Two of those giving the best reactions are shown in the table together with several additional tests by duodenal administration not previously reported. In all of the four cases reported the patients were on constant diets. The results show : (1) that insulin contained in 0.1 or 0.2 per cent HCl is absorbed from the human intestine; (2) that addition of alcohol to 5 to 8 per cent increases the absorption somewhat; (3) that alcohol alone, however, produces a drop in blood sugar but only a slight effect on the 24 hour elimination of sugar by the kidney; (4) that insulin combined with a weak organic acid or acid salt, the whole contained in an enteric coating which survives the stomach for at least three hours, can be absorbed in sufficient amount to lower blood sugar and urine sugar very materially.

A Note on the Detection of Cyanides

Since hydrocyanic acid is both a very weak and an easily volatile acid, it would seem that one ought to be able to separate the cyanides from admixture with these other substances by making the solution containing them slightly acid and distilling off the hydrocyanic acid. Any of the well-known tests could then be applied to the distillate. There is this difficulty, however, that ferro, and ferricyanides and sulfocyanates will all yield hydrocyanic acid when an acid solution containing them is distilled at the boiling temperature. Hilger and Tamba state that cyanides may be detected in the presence of ferroand ferricyanides by acidulating with tartaric acid and passing a current of carbon dioxid through the solution, taking care not to warm the solution above sixty degrees. On account of the restricted conditions this method is not adapted to use by students. The cyanides are salts of very weak acid, while the ferroand ferricyanides and sulfocyanates are salts of strong acids; as the result of this, the cyanides are, upon going into solution in water, largely hydrolytically split up with the formation of much free hydrocyanic acid, while the hydroferrocyanic acid, etc., are not formed. As a result of this, hydrocyanic acid will distil from a solution of potassium cyanide although the latter is highly alkaline. The hydrolysis of all salts of weak acids is greater if there is present at the same time in the solution the cations of some weak base; hence the hydrocyanic acid will distil much more readily from the potassium cyanide solution if there be added to the latter some ammonium chlorid.

THE RELATION BETWEEN THE DECOMPOSITION-TENSION OF SALTS AND THEIR ANTIFERMENTATIVE PROPERTIES

Line 9 on page 446, Volume X, should read: "addition of the neutral salts of weak monobasic, dibasic, and tribasic acids."