The reaction of kaolin clay with orthophosphoric acid

Conclusions Orthophosphoric acid reacts with kaolinite clay already at room temperature. The reaction results in the dissociation of some kaolinite and the formation of acid aluminophosphates, its rate is at maximum during the first 4–10 days of the storage of the composition of clay with the acid, and it ceases when the composition is stored for longer periods.The triderivative of aluminophosphate begins to form only on heating above 100°C. At a temperature of 400°C and higher it forms more rapidly while the proportion of mono- and diderivatives of aluminophosphates diminishes.The fact that in compositions of kaolinite clay with orthophosphoric acid in storage only water-soluble acid aluminophosphates are formed and triderivative of aluminophosphate is absent makes it possible to produce clay-containing aluminosilicate compositions containing orthophosphoric acid at refractory plants in ready-for-use form.Translated from Ogneupory, No. 7, pp. 43–48, July, 1977.     

The electrobrightening of copper in orthophosphoric acid

The electrobrightening of copper in orthophosphoric acid was studied at several electrolyte concentrations, temperatures and current densities. Stress-free electrolytic copper plates were used in a rectangular plexi-glass cell, through which a constant current was passed. The results show that there is a critical bath temperature (27° C) at which the surface has a maximum brightness, that an increase in the current density above a limiting value has only a slight effect on surface brightness and that brightness increases with acid concentration.     

Mechanism of linoleic acid hydroperoxide reaction with alkali

Treatment of (13S,9Z,11E)-13-hydroperoxy-9,11-octadecadienoic acid (13S-HPODE) with strong alkali resulted in the formation of about 75% of the corresponding hydroxy acid, (13S,9Z,11E)-13-hydroxyl-9,11-octadecadienoic acid (13S-HPODE), and the remaining 25% of products was a mixture of several oxidized fatty acids, the majority of which was formed from (9Z,11R,S,12S,R)-13-oxo-11, 12-epoxy-9-octadecenoic acid by Favorskii rearrangement (Gardner, H.W.,et al. (1993)Lipids 28, 487–495). In the present work, isotope experiments were completed in order to get further information about the initial steps of the alkali-promoted decomposition of 13S-HPODE.1. Reaction of [hydroperoxy-¹⁸O₂]13S-HPODE with 5 M KOH resulted in the formation of [hydroxy-¹⁸O]13S-HPODE and [epoxy-¹⁸O](9Z,11R,S,12S,R)-13-oxo-11, 12-epoxy-9-octadecenoic acid;2. treatment of a mixture of [U-¹⁴C]13S-HPODE and [hydroperoxy-¹⁸O₂]13S-HPODE with KOH and analysis of the reaction product by radio-TLC showed that 13S-HPODE was stable under the reaction conditions and did not serve as precursor of other products;3. reaction of a mixture of [U-¹⁴C]13-oxo-9,11-octadecadienoic acid (13-OODE) and [hydroperoxy-¹⁸O₂]13S-HPODE with KOH resulted in the formation of [U-¹⁴C-epoxy-¹⁸O](9Z,11R,S,12S,R)-13-oxo-11,12-epoxy-9-octadecenoic acid;4. treatment of a mixture of [hydroperoxy-¹⁸O₂] 13S-HPODE and [carboxyl-¹⁸O₁]13S-HPODE with KOH afforded (9Z,11R,S,12S,R)-13-oxo-11,12-epoxy-9-octadecenoic acid having an¹⁸O-labeling pattern which was in agreement with its formation by intermolecular epoxidation. It was concluded that (9Z,11R,S,12S,R)-13-oxo-11, 12-epoxy-9-octadecenoic acid is formed from 13S-HPODE by a sequence involving initial dehydration into the α,β-unsaturated ketone, 13-OODE, followed by epoxidation of the Δ¹¹ double bond of this compound by the peroxyl anion of a second molecule of 13S-HPODE. Rapid conversion of hydroperoxides by alkali appreared to require the presence of an α,β-unsaturated ketone intermediate as an oxygen acceptor. This was supported by experiments with a saturated hydroperoxide, methyl 12-hydroperoxyoctadecanoate, which was found to be much more resistant to alkali-promoted conversion than 13S-HPODE.     

Thermal transformations during the interaction of chamotte and orthophosphoric acid

Conclusions Up to 300°C chamotte does not react with orthophosphoric acid. In the range 300–800°C crystallization of the type SiO₂·P₂O₅ occurs. With further increase in temperature the silicophosphate dissolves, and at 1030°C is converted from the low- to the high-temperature form, and at 1200°C it changes completely into the melt.Starting from 500°C the mullite decomposes. The intensity of the mullite line at 1400°C is slight.In the range 700–1000°C a large quantity of liquid phase, formed during decomposition of the silicophosphates and mullite, sharply depresses the refractoriness-under-load and increases their shrinkage.At 1200°C AlPO₄ crystallizes in the cristobalite form. An increase in the quantity of AlPO₄ increases the refractoriness-under-load of the specimens.Mixtures of chamotte and orthophosphoric acid after firing at 1400°C contain (in reducing order) AlPO₄ (cristobalite form), cristobalite, mullite, and quartz; they may be recommended as low sintering mortars.Translated from Ogneupory, No.2, pp. 39–43, February, 1970.     

Properties of aluminophosphate concretes containing various types of orthophosphoric acid

Conclusions The type of orthophosphoric acid has the maximum influence on the properties of corundum concretes, a lower influence on high-alumina concretes, and practically no influence on quartz-clay concretes. It is desirable to use wet-process orthophosphoric acid for refractory concretes. The excellent properties of concretes in the system A1₂O₃-SiO₂ based on this acid which is also cheaper enabled us to recommend it for preparing refractory concretes.The advantage of using H₃PO₄ of various types for corundum concretes is determined by the requirements placed on them in actual working conditions.Translated from Ogneupory, No.6, pp. 58–61, June, 1970.     

Deodorization performance of charcoal particles loaded with orthophosphoric acid against ammonia and trimethylamine

A deodorant was prepared by drying charcoal particles after dipping in aqueous H₃PO₄ solutions. The deodorization performances of the samples against NH₃ and (CH₃)₃N odor gases were examined by a detection test tube method and compared with those of a conventional coconut shell-derived active carbon loaded with H₃PO₄ in the same manner. The charcoal particles with H₃PO₄ exhibited higher performances than those of the other against both the odor gases. Ammonia gas was caught on the sample surface through reaction with the loaded H₃PO₄ to form NH₄H₂PO₄ and further (NH₄)₂HPO₄ but the deodorization mechanism for (CH₃)₃N could not be decided. The high performances of the charcoal particles loaded with H₃PO₄ were due to its characteristic porous structure consisting of large pores, i.e., such pores were suited for loading a large amount of H₃PO₄ and were not apt to be blocked by the loaded H₃PO₄. Also large pores were not blocked by expansion of H₃PO₄ on the pore surface through the deodorization reactions. The active carbon being composed of a large number of micropores did not exhibit these advantages.     

Esterification of viscose fibres with orthophosphoric acid and study of their physicochemical and mechanical properties

Esterification of viscose fibres with aqueous solutions of orthophosphoric acid and urea at different ratios of components was investigated. It was shown that in phosphorylation of cellulose with these solutions, one-substituted cellulose phosphates are formed and a side process of formation of cellulose carbamates takes place together with accumulation of phosphate groups. A decrease was found in the mechanical strength of the phosphorylated cellulose preparations and the degree was a function of the concentration of orthophosphoric acid and urea as the phosphorylating solution. Phosphorus-containing viscose fibres (up to 0.5 mmole/g of phosphate groups) obtained in solutions of orthophosphoric acid and urea with a 0.25–0.63 and 3.33–4.17 M concentration have the most satisfactory mechanical properties and stability in phosphate buffer with pH 7.5. __________ Translated from Khimicheskie Volokna, No. 1, pp. 26–30, January—February, 2007.