Concentration Of Sodium Hydroxide Solution Research Articles

Effect on the Concentration of Alkaline Solution in the Hot Alkaline Refining

The hot alkaline refining of prechlorinated sulphite pulp was studied with the various concentrations of alkaline solutions. The results are as follows : 1) If an equal amount of sodium hydroxide based on moisture-free pulp is used in the treatments, higher refining effect is obtained with increase in pulp consistency.2) The refining reaction scarcely goes on, when the concentration of sodium hydroxide solution is reduced to 0.05% or less on the course of hot alkaline treatment.3) A certain correlation seems to exist between the yield and the alpha cellulose content of refined pulp, and the amount of dissolving from pulp is a function of the amount of alkali consumed in the treatment. Therefore, the highest alpha cellulose content of pulp, expected within a range of adopted conditions, may be determined by the amount of sodium hydroxide based on moisture-free pulp using in the hot alkaline refining.4) The velocity of refining reaction during the hot alkaline treatment is influenced by the amount of remained pulp and the concentration of alkaline solution.5) The higher the concentration of alkaline solution adopted, the quicker the reaction takes place, and the velocity does not reduce to the corresponding level, even if the alkali concentration falls down on the course of refining. This is due to the fact that the structure of cellulose fiber is loosened by the higher alkaline solution at the beginning of treatment.

ON THE SO-CALLED SULFIDATION-RESISTANCE OF DISSOLVING PULP BY EMULSION XANTHATION

The sulfidation-resistance value (S-W), proposed by Bartunek as a measure of reactivity of dissolving pulp, is the amounts of undissolved residue of pulp after emulsion xanthation at the definite concentration of sodium hydroxide solution, sufficient to mercerize cellulose, with 25% of carbon disulfide based on the pulp. So the Bartunek's S-W shows only a point on the emulsion xanthation solubility curve (S-W curve) as a function of the amounts of carbon disulfide added. In the previous paper, the significance of S-W curve as a measure of reactivity or filterbility of viscose from the pulp was studied.In this paper, the relation between S-W curve and Bartunek's S-W is studied in order to research the significance of Bartunek's S-W as a measure of reactivity of dissolving pulp. The results are as follows:Bartunek's S-W correlates not only to the amounts of carbon disulfide required for dissolving 50% of pulp, but also A1, A2 and A3. Here, A1 and A2 are the average “dissolved-distances” per unit amount of carbon disulfide on the first and second inflexion points of calculated S-W curves respectively, and A3 is the average amount of the dissolved per unit amount of carbon disulfide during the reaction (see Fig. 5). However Bartunek's S-W has no correlation to the characteristics of S-W curve, obtained in the previous paper as to the state of viscose solution.From the above, the following conclusion may be drawn. Bartunek's S-W gives only an average measure of solubility in emulsion xanthation, and has no definite significance as a measure of reactivity of dissolving pulp or a measure of filterbility of viscose prepared from the pulp.

EMULSION XANTHATION OF PULP

In the previous paper, it was found that the marcerization-resistance curve (M-W curve) obtained by varying concentrations of sodium hydroxide solution in emulsion xanthation is influenced by socalled lateral order distribution of pulp.According to O. Samuelson et a12)., “the reason why the pulp viscosity can be used as a criterion of filterbility of a viscose prepared from the pulp is that the decrease in viscosity in a given, process, e. g. the ordinary sulfite cooking, is parallel to the attack upon the fiber structure.” They added also that “experiments on emulsion xanthation can be used as a complement and be of considerable value for the comparison of similar types of the biological structure of which has been, attacked to a different degree.”It seems to be very important for estimating the value of M-W curve as an indication of reactivity of pulp, how the opinion mentioned above can be adapted in the comparison of different types, of pulps prepared from different raw materials or by different processes.In order to obtain the relation between M-W curve and average degree of polymerization of cellulose, dissolving sulfite pulp (DSP), dissolving sulfate pulp (DKP), linters pulp (Li. P) and mercerized DSP were degradated by various treatments to various degrees, and M-W curves of these samples were determined in this paper.The results obtained are as follow:The solubility of pulp in emulsion xanthation increases as average degree of polymerization of cellulose is lowered. Influence of the differences of lateral order found amoung DSP, DKP and Li. P upon the solubility in emulsion xanthation do not diminish, though each pulp has been hydrolyzed with dilute sulfuric acid solution and cellulose has been degradated as low as 300 of average degree of polymerization of cellulose. The fact shows the influence of fine structure of cellulose on M-W curve is very significant. Then M-W curves of DKP treated with dilute sulfuric acid solution, dilute ligninsulfonic acid solution or ultra violet ray, and of DSP hydrolyzed with dilute sulfuric acid solution after mercerization or aged in air after mercerization were determined. It was found also that the properties of fine structure of cellulose has more effect on M-W curve than average degree of polymerization of cellulose. For the similar type pulps degradated with similar type treatments, the solubility in emulsion xanthation is parallel to average degree of polymerization of cellulose, but for the different types of pulp, M-W curves are governed mainly by the fine structure of cellulose. This means M-W curve can not be used as a criterion of filterbillity of a viscose preparad from the different type of pulp.

Interaction of Picric Acid with Sodium Hydroxide in Water

IN a previous paper1, it was reported that a 360-mµ band of picric acid in water was found to shift to the red by about 35 mµ by addition of a concentrated solution of sodium hydroxide. Interaction of picric acid with sodium hydroxide in water has, therefore, been investigated by measurement of the absorption spectra of the picric acid solutions at various concentrations of sodium hydroxide. The results are shown in Fig. 1.

ON THE SO-CALLED SULFIDATION-RESISTANCE VALUE OF DISSOLVING PULP BY EMULSION XANTHATION

The sulfidation-resistance value (S-W), proposed by R. Bartunek as an estimating method of reactivity of dissolving pulp, is the amounts of undissolved residue of pulp after emulsion xanthation at the definite concentration of sodium hydroxide solution, sufficient to mercerize cellulose, with 25% of carbon disulfide based on the pulp. The Bartunek's S-W shows only a point on the emulsion xanthation soluhility curve (S-W curve) as a function of the amount of carbon disulfide added. The significance of S-W curve and the relation between S-W curve and Bartunek's S-W must be investigated to make clear the significance of Bartunek's S-W as a estimating method of reactivity in dissolving pulp. In this paper, the relation between sulfidation and dissolution in S-W curve is examined, and an adequate expression method of characteristics of S-W curve is proposed.The results are as follows:1) S-W curve can be converted to the straight line on the following assumptions. a) Sulfidation and dissolution occur from the outer surface of fiber and advance to its center, namely fiber is peeled off gradually from the surface. b) If the amount of dissolved cellulose is expressed by the distance from the surface in radial direction (dissolved distance), the distance is proportional to the amount of carbon disulfide added in emulsion xanthation.2) The converted S-W curve (shown as calculated curve in Figs. 2, 3, 5 and 6) is consisted of three lines, and its inflexion-points correspond to the points at which distinctly γ-value of undissolved residue varies. This means that the reaction of pulp in emulsion xanthation is consisted of three steps of sulfidation and dissolution processes. In the last step, most of pulps show sulfidation-resistance.3) If sulfidation and dissolution of pulp advance on the assumption described above, the contents of S-W curve are as follows:When a ratio of the degree of sulfidation and dissolution is more uniform over the whole range of solubility on emulsion xanthation, the carbon disulfide is less consumed for the complete dissolution of pulp. How far to the fiber the sulfidation advance during emulsion xanthation, in comparison with the degree of dissolution (dissolved distance), determines the amount of carbon disulfide required for 100% dissolution of pulp, (1/A3) shown in Fig. 6.The ununiformity of converted S-W curve, (A2/A3-1) shown in Fig. 6, express the ununiformity of ratio of sulfidation and dissolution during emulsion xanthation process.4) From the above, S-W curve can be characterized by A3 and (A2/A3-1).

Chemical Modification of Flax Cellulose I–Action of Acrylonitrile, Chloroacetic Acid, and β–Propiolactone

The reaction of flax yarn with acrylonitrile, chloroacetic acid, and β–propiolactone in presence of sodium hydroxide as catalyst has been studied. The results are compared with those obtained with cotton in earlier work. Under the experimental conditions used, measurable differences in reactivity between the two fibres are apparent. The cause of this difference in reactivity has been investigated and is explained by consideration of the effect of different concentrations of sodium hydroxide solutions on the two fibres. In general, for a given alkali concentration flax absorbs more sodium hydroxide and water than does cotton. This gives a greater change in the fine structure of the flax fibre produced by mercerising strengths of alkali. The effect of mercerising–strength sodium hydroxide on the nodes present in flax fibre, which act as major points of entry to the fibre, is also pointed out.

Sur le Mécanisme d'Adsorption et de Désorption des Solutions aqueuses de Soude dans les Fibres de Cellulose–Equilibres de Fixation de la Soude (3éme Comunication)

AbstractThis is the third paper of this series published in this journal. The two previous papers dealt with a theory of interaction between cellulose fibers and aqueous solutions of sodium hydroxide.This interaction depends on several factors: For a given temperature, accessibility phenomena limit the penetration of soda solutions into native fibers (not previously mercerised) according to concentrations and types of fibers. An equilibrium for the fixation of sodium hydroxide is established within the parts of the fibers where penetration has occured. The equilibrium conditions are strictly independent of the type of fiber used. Fibers previously mercerised are fully accessible whatever may be the concentration of sodium hydroxide solution used.In the first part of this paper it is shown that the equilibrium equation previously set up, quantitatively fits the observed data.Desorption phenomena are then studied: displacement of 20% sodium hydroxide solutions from mercerised fibers by more dilute solutions. New accessibility phenomena are pointed out. A sodium hydroxide solution (concentration C < 20%) can penetrate or displace a fraction y only of the fiber soaked with 20% sodium hydroxide solutions. Values of y vs. C are givenA simple thermodynamic treatment explains the observed phenomena.

Corrosion of silicate glasses by alkaline solutions Communication 5. Effect of alkali concentration on the degree of destruction of glass

1. An increase in concentration of sodium hydroxide solutions from 0.5 to 10 N affects the degree of corrosion of silicate glasses variously: glasses rich in silica are attacked proportionally to the alkali concentration, the destructive action on glasses rich in lead, zinc, cadmium, or magnesium is at first increased and then retarded as a result of the accumulation in the solution of anion-inhibitors and the formation of protective layers of magnesium hydroxide, and glasses rich in calcium, strontium, or bariumare attacked to the same extent by all solutions in the concentration range investigated. 2. An increase in the concentration of strontium or barium hydroxide solutions leads to a decrease in the corrosion of silicate glasses as a result of the formation on the surface of the glass of alkali-stable compounds.

EMULSION XANTHATION OF PULP-INFLUENCE OF FINE STRUCTURE ON M-W CURVE

M-W curve, obtained by varying concentrations of sodium hydroxide solution in emulsion xanthation of pulp, may be influenced by some characteristics of pulp, such as distribution of cellulose chain length, morphological and fine structure, etc. In this paper, the relation between M-W curve and the fine structure was studied.The curve can be characterized by its position and shape. The concentration of sodium hydroxide solution, in which half of pulp goes into solution, was adopted for expression of the position of the curve, and is symbolized with [C]0. To express the shape of the curve, we adopted the parameter (n0) obtained by the procedure, which was proposed by H. Takenaka for representaion of the distribution curves of degree of polymerization of high polymers and was modified by us. In this paper the parameter (n0) means mainly the slope of the curve.The relations between the fine structure of pulp and (n0) and [C]0, are as follows;(1) The slope (n0) of M-W curve decreases with increasing the ununiformity of lateral order distribution and the amount of low ordered region (Fig. 9, 12).(2) If the average lateral order level [C]H becomes lower, the position of M-W curve tends to move toward the lower sodium hydorxide concentation range, namely [C]0 decreases (Fig. 1). However the position of M-W curve [C]0 is not only controlled by the average lateral order level [C]H, but also by the distribution of lateral order, especially the relation between the specific surface area and the lateral order level of pulp.

THE EVALUATION OF LATERAL ORDER DISTRIBUTION IN NATIVE CELLULOSE BY THE EMULSION XANTHATION METHOD

To evaluate lateral order distribution in native cellulose, fractional dissolution method by the emulsion xanthation was applied with varying concentrations of sodium hydroxide solution. From some preliminary experiments the following conditions were found to be suitable for the purpose. Fifty ml of sodium hydroxide solution and 1.0ml of carbon disulfide are added to 0.5g methanolyzed cellulose sample, and treated for 6 hours at 20_??_25°C. The undissolved residue was washed with sodium hydroxide solution of same concentration as used in emulsion xanthation.Lateral order distribution curves obtained by this method agree fairly well with that of the fractional dissolution method proposed by T. Yurugi and H. Maeda.

Kinetic Studies on Formation of Black‐Oxide Coatings on Mild Steel in Alkaline Nitrite Solutions

The formation of black‐oxide (magnetite) coatings on mild steel in hot concentrated solutions of sodium hydroxide and sodium nitrite was studied over the temperature range 130°–150°C. The following mechanism is proposed for the over‐all reaction: Of the total iron dissolved in step [1], only about 30% was converted to black oxide on the surface. Values of the rate constant for step [1] were obtained from plots of total iron dissolved vs. time. Plots of the initial rates (oxide‐free surface) vs. 1/T were linear, with an energy term of 41 kcal/mole. As the oxide coating built up, the rates dropped to a fraction of the initial rate and the energy term increased sharply. For thicker films the rates are apparently controlled by diffusion of the reactants through the film.

Sur le mécanisme de fixation de la soude sur les fibres de cellulose‐mercerisation ‐ structure des solutions aqueuses de soude. (2ème Communication)

AbstractIn the present work, conclusions from a former paper are examined in the light of new results. Aqueous solutions of sodium hydroxide (concentrations from 5 to 35%) appear as ion‐pairs Na+, OH‐ with an average solvation number n changing with concentration. Sodium hydroxide would bind to the cellulose macromolecules as mixed hydrates: 3 water molecules from the solvation shell being exchanged with 3 cellulose —OH groups. The thermodynamic aspect of native cellulose fiber accessibility to soda solutions is briefly considered together with the change of crystal lattice and macromolecular structure during the mercerization process. Possible formation of true sodium cellulosate in highly concentrated (40%) sodium hydroxide solutions is contemplated. Fixation of more than one mole NaOH per C6 group has never been observed.

アミン-水-苛性アルカリ系の平衡 (第6報)

Mutual solubility of a binary system of heptylamine and water in the temperature range of 0° to 90° was measured and a peculiar solubility curve was obtained. The jelly-like state formed in the concentration range of 30-70w% of heptylamine was studied and the presence of heptylamine heptahydrate was assumed.Mutual solubility of a ternary system of heptylamine-water-sodium hydroxide was determined at 20.3, 40.2, 59.7, and 79.4° and their equilibrium diagram was obtained. A smooth, conjugation curve was also obtained. A conjugation curve drawn with the concentration of the amine in the upper layer and that of sodium hydroxide in the lower layer as the molar fraction units, gave a straight line within a certain concentration range and the straight lines at each temperature were found to be approximately parallel to each other. The concentration of heptylamine present in equilibrium with a definite concentration of sodium hydroxide solution increases with the increase in temperature and the concentration of heptylamine in the upper layer was greater, the greater the concentration of sodium hydroxide in the lower layer when the temperature was constant.

アミン-水-苛性アルカリ系の平衡 (第8報)

Mutual solubility of pyridine-water-sodium hydroxide system was measured at 0, 30, 60, and 90°, and their equilibrium diagrams and conjugation curves were obtained. Mutual solubility of pyridine and water is markedly affected by temperature and the presence of caustic alkali. At a definite temperature, the mutual solubility decreases with an increase in the concentration of sodium hydroxide, while the concentration of pyridine in equilibrium with a definite concentration of sodium hydroxide solution increases with the increase of temperature.

アミン-水-苛性アルカリ系の平衡 (第5報)

Mutual solubilities in the nicotine-water-sodium hydroxide system at 0°, 30°, 60°, and 90° were measured and equilibrium diagrams were drawn. Conjugation curve, drawn with the concentration of sodium hydroxide in the lower layer of the conjugate solution as the abscissa and the concentration of nicotine in the upper layer as the ordinate, was found to become linear within a limited concentration range when the concentration unit is shown by molar fraction, although the curve deviates from the straight line in the extremely low or high concentration. These curves at various temperatures run almost parallel. The composition of the conjugate solution comes to be over 90% nicotine in the upper layer when the amount of sodium hydroxide in the lower layer is over 20%, and the lower layer is practically devoid of nicotine, with none of sodium hydroxide in the upper layer. Except in the case of 0°, the upper layer present with 35-40% sodium hydroxide solution is almost 100% nicotine. The concentration of nicotine in equilibrium with a definite concentration of sodium hydroxide solution increases with the increase of temperature. The present experimental results have offered advantageous method for the isolation and dehydration of nicotine.

Improved process for re‐refining cottonseed oil for the removal of color bodies

SummaryA method for removing color from neutralized and degummed cottonseed oil is described. Data included shows color removal to be directly correlated to: a) concentration of sodium hydroxide solution, b) length of time of agitation, and c) speed of agitation in r.p.m. The degree of color removal is inversely correlated to the temperature of the oil during agitation with sodium hydroxide solutions. Laboratory findings have been put to practical use in the refinery for over a year with satisfactory results.

The Methyl Ethers of D-Glucose

Publisher Summary This chapter discusses that methylation will connote the replacement of the primary or secondary alcohol groups of a sugar by methoxyl groups. The derived methyl glycoside does not behave as an ether and the original sugar may be regenerated from it by hydrolysis with aqueous acid. The methods of synthesis and the proofs of constitution of all the known methyl ethers of D-glucopyranose and D-glucofuranose are presented in the chapter. The two most common groups liable to be modified by methylation are the reducing group and any ester groups that may be present in the molecule. Reducing sugars are disrupted under alkaline conditions, oxidized by silver oxide and converted to aldehyde-ammonias and 1-amino derivatives by liquid ammonia. The most generally applicable method for the methylation of carbohydrates is that of Haworth, in which the methylating agents are dimethyl sulfate and concentrated sodium hydroxide solution. This method possesses the advantages that the solvent is water and that, under appropriate conditions, it is suitable for the direct methylation of reducing sugars.

Anodic Behaviour of Mild Steel Strongly Alkaline Solutions

In connexion with the well-known intercrystalline failure of mild steel in concentrated solutions of sodium hydroxide, it would appear that a study of the anodic behaviour of iron in such solutions might lead to results of considerable interest. A search of the literature soon reveals, however, that but little attention has been devoted to this matter. The work of Grube and Gmelin1, who carried out a careful and extensive investigation in this field, is therefore of special importance. These workers obtained evidence that anodic dissolution takes place in two distinct potential stages: at low current densities electrolysis proceeds at a potential of about — 0·85. V. (hydrogen), whereas at higher values it changes suddenly to + 0·65 V., when oxygen evolution commences. The critical current density was found to increase rapidly with temperature. Evidence is adduced by Grube and Gmelin that the lower (more negative) potential stage is associated with the formation of ferrous ion, and the higher with oxidation to the hexavalent ion Fe6.; anionic complexes being formed having the probable compositions (FeO2)″ and (FeO4)″ respectively.

Specific Heats and Heats of Dilution of Concentrated Sodium Hydroxide Solutions

Specific Heats and Heats of Dilution of Concentrated Sodium Hydroxide Solutions

CELLULOSE SHEET SWELLING Effect of Temperature and Concentration of Sodium Hydroxide Solutions

CELLULOSE SHEET SWELLING Effect of Temperature and Concentration of Sodium Hydroxide Solutions