Viscosity hydroxide solutions

Carbon disulphide is an excellent solvent for fats, oils, rubber, sulphur, bromine and iodine, and is used industrially as a solvent for extraction. It is also used in the production of viscose silk, when added to wood cellulose impregnated with sodium hydroxide solution, a viscous solution of cellulose xanthate is formed, and this can be extruded through a fine nozzle into acid, which decomposes the xanthate to give a glossy thread of cellulose. 

Several cellulose esters (qv) are prepared commercially. Cellulose xanthate [9032-37-5] is made by reaction of cellulose swollen in 8.5—12% sodium hydroxide solution (alkaU cellulose [9081-58-7J) with carbon disulfide and is soluble in the alkaline solution in which it is made. When such a solution, termed viscose, is introduced into an acid bath, the cellulose xanthate decomposes to regenerate cellulose as rayon fibers or cellophane sheets (see Fibers, REGENERATED CELLULOSICS). 

Cotton linters and viscose grade wood pulp were partially xanthated under different conditions to study the effect of the degree of substitution on the acrylamide grafting of these pulps. Sodium hydroxide solutions of 2%, 4%, and 6% were used and the vapor phase xantha-tion process was applied for 0.5, 1.0, 1.5, and 2.0 h for... 

A large quantity (700 kg) of the chlorophenol, left in contact with cone, sodium hydroxide solution for 3 days, decomposed, attaining red heat and evolving fumes which ignited explosively. Although this could not be reproduced under laboratory conditions, it is believed that exothermic hydrolysis to the hydroquinone (possibly with subsequent aerobic oxidation to the quinone) occurred, the high viscosity of... 

Viscose Also known as the Cross-Bevan-Beadle process. A process for making regenerated cellulose fibers. The product has been known by the generic name rayon since 1924. Cellulose, from cotton or wood, is first reacted with sodium hydroxide ( mercerization), yielding alkali cellulose. This is dissolved in carbon disulfide, yielding cellulose xanthate, which is dissolved in sodium hydroxide solution. Injection of this solution (known as viscose... 

Xylan xanthate can be made by the action of carbon disulfide on xylan in sodium hydroxide solution. Analysis of the products indicates substitution below the diester stage, but the reaction appears similar to that occurring with cellulose.119 120 However, neither Heuser and Schorsch119 nor Dorr121 find that xylan gives a viscose-like solution. 

In 1891, British chemistry Cross and Bevan discovered that wood pulp when treated with sodium hydroxide solution and carbon disulphide, gets converted into cellulose xanthate. When cellulose xanthate is dissolved in caustic soda solution it gives a viscous solution that could be spun to form fibres called Viscose Rayon. Rayon is produced in large scale today in many countries including India. Rayon (also know as viscose) is in fact regenerated cellulose. 

Uses and Physiological Properties of Carbon Disulphide.—Besides its employment as a solvent (see p. 260), carbon disulphide is used extensively in the manufacture of viscose silk. Viscose is a solution of the sodium salt of the cellulose ester of thiolthioncarbonic acid (p. 268) in water or dilute aqueous sodium hydroxide, or it may be described as an aqueous solution of the sodium salt of cellulose xanthic acid. For its production cellulose is steeped in concentrated sodium hydroxide solution and then pressed, the product being called alkali-cellulose and the formula CeH10O5.NaOH assigned to it. This is converted into viscose by treatment with carbon disulphide, when the colour changes to golden yellow ... 

To a 250 ml flask equipped with a stirrer, a thermometer, a water condenser and Dean-Stark trap was added 11.42 g of 4.4 -isopropylidenediphenol (0.05 moles), 13.1 g of a 42.8% potassium hydroxide solution (0.1 mole KOH), 50 ml of dimethyl sulfoxide and 6 ml of benzene. The reaction mixture was kept under an atmosphere of nitrogen and the water was azeotroped oft over a 3 to 4 hours period (130—135° C). At the end of this time the reaction mixture consisted of the potassium salt of the biphenol and was essentially anhydrous. After cooling the mixture there was added 14.35 g (0.05 moles) of 4.4 -dichlorodiphenyl sulfone and 40 ml of anhydrous dimethylsulfoxide. The reaction mixture was maintained, under a nitrogen atmosphere, between 130 and 140° C with stirring for 4 to 5 hours. The viscous orange solution was then poured into 300 ml of water in a Waring Blendor and the polymer separated by filtration and dried at 110° for 16 hours. A yield of 22.2 g (100%) of polymer with a reduced viscosity in chloroform (0.2 g per 100 ml at 25°) of 0.59 was obtained. 

Investigations by X-ray methods have indicated that alginic acid possesses a fiber structure analogous to that of cellulose.86 An estimate of the molecular weight was obtained by Heen87 from a study of the viscosity of solutions of the acid in 2 JV sodium hydroxide. The values found, (14,100-15,400), corresponded to a degree of polymerization of about 80, but these were considered to be approximations only, as it was uncertain whether or not Staudinger s formula could be applied. 

The need for greater accuracy in determining the intrinsic viscosity, [ij], of cellulose dispersed in cuprammonium hydroxide solution led... 

Fiori and Farouq Ali (73) proposed the emulsion flooding of heavy-oil reservoirs as a secondary recovery technique. This process is of interest for Saskatchewan heavy-oil reservoirs, where primary recovery is typically 2-8%. Water-flooding in these fields produces only an additional 2-5% of the original oil in place because of the highly viscous nature of the oil. In laboratory experiments, a water-in-oil emulsion of the produced oil is created by using a sodium hydroxide solution. The viscous emulsion formed is injected into the reservoir. Its high viscosity provides a more favorable mobility ratio and results in improved sweep of the reservoir. Important parameters include emulsion stability and control of emulsion viscosity. 

Apparently, there is no influence of oxygen during the preparation of the fractions in the chloral hydrate procedure, as judged from the values of intrinsic viscosity of the experiments given in Table III. Furthermore, it may be noted that the amylopectin fractions obtained by this method are insoluble in hot water (as well as in cold 1.0 AT potassium hydroxide solution). ... 

---