Synthesis of silicon-containing esters of phosphorus acids and study of their thermal stability. 3. Thermal rearrangement of triorganosilylmethyl esters of diphenyl phosphoric acid

1989 ◽  
Vol 38 (7) ◽  
pp. 1527-1532
Author(s):  
M. I. Kabachnik ◽  
L. S. Zakharov ◽  
G. N. Molchanova ◽  
T. D. Drozdova ◽  
P. V. Petrovskii
Keyword(s):  
Thermal Stability ◽  
Phosphoric Acid ◽  
Thermal Rearrangement ◽  
Esters Of Phosphorus Acids

scholarly journals STUDY OF THERMAL DECOMPOSITION PRODUCTS OF NITROGEN-PHOSPHORUS-POTASSIUM FERTILIZERS BASED ON AMMONIUM NITRATE BY X-RAY DIFFRACTUON

2017 ◽  
Vol 61 (1) ◽  
pp. 72
Author(s):  
Konstantin G. Gorbovskiy ◽  
Alena S. Ryzhova ◽  
Andrey M. Norov ◽  
Denis A. Pagaleshkin ◽  
Valentina N. Kalinina ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Phosphoric Acid ◽  
Ammonium Nitrate ◽  
Confined Space ◽  
Decomposition Products ◽  
X Ray ◽  
Thermal Decomposition Products ◽  
Nitrogen Phosphorus ◽  
Thermal Stability Of

Complex mineral ammonium nitrate-based fertilizers are complex multicomponent salt systems possessing low thermal stability and prone to self-sustaining decomposition. This leads to the need to increase the requirements for fire and explosion safety in their manufacture, storage and transportation, caused by the fact that ammonium nitrate is a solid oxidant able to support a combustion, and its heating in confined space can lead to detonation. Components that make up such fertilizers can both reduce (phosphates and ammonium sulfate) and accelerate (chlorine compounds) decomposition of ammonium nitrate. Thus, the thermal stability of fertilizers based on ammonium nitrate largely depends on the ratio of the components that make up its composition or formed as a result of the chemical reaction. The simplest way to reduce the content of ammonium nitrate and increase the thermal stability of fertilizer without changing the content of essential nutrients is to increase the degree of phosphoric acid ammoniation. In this paper, the phase composition change of grade 22:11:11 nitrogen-phosphorus-potassium fertilizer obtained with different ammoniation degree in the process of thermal decomposition was studied by X-ray phase analysis. To obtain this fertilizer, wet-process phosphoric acid obtained sulfuric acid attack of the Khibin apatite concentrate by a hemihydrate method is used. It is shown that an increase in the ammoniation degree has a significant effect on the exothermic decomposition of ammonium nitrate and the amount of material that is released into the gas phase. The phases formed at each stage of the decomposition are determined.Forcitation:Gorbovskiy K.G., Ryzhova A.S., Norov A.M., Pagaleshkin D.A., Kalinina V.N., Mikhaylichenko A.I. Study of thermal decomposition products of nitrogen-phosphorus-potassium fertilizers based on ammonium nitrate by X-ray diffractuon. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 1. P. 72-77

Surface Modification of Bacterial Cellulose Sheets With Various Fire Retardants

2020 ◽  
Vol 13 (2) ◽  
Author(s):  
Eser Sözen ◽  
Gökhan Gündüz ◽  
Deniz Aydemir ◽  
Ahmet Can
Keyword(s):  
Thermal Stability ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Thermogravimetric Analysis ◽  
Phosphoric Acid ◽  
Bacterial Cellulose ◽  
Weight Percent Gain ◽  
Weight Percent ◽  
Fire Retardants ◽  
Freeze Dried

Abstract This study investigated the effects of various fire retardants including Firetex®, phosphoric acid, and nanoboron nitride on the thermal and morphological properties of bacterial cellulose (BC) sheets. Hestrin and Schramm medium was inoculated with Gluconacetobacter hansenii and the medium with the bacteria was incubated for 14 days. The obtained BC sheets were freeze-dried and then the dried sheets were immersed with Firetex®, phosohoric acid, and nanoboron nitride for a day. The sheets were once again freeze-dried and weight percent gain (WPG) of the sheets was calculated by using wet and dried weights. The morphological characterization, thermal properties, and structural changes of the obtained sheets were also investigated with scanning electron microscopy (SEM), thermogravimetric analysis, and Fourier-transform infrared spectroscopy, respectively. The weight percent gain was found to increase 31% for the samples with boron nitride and 1040% for the samples with phosphoric acid after the impregnation. The thermogravimetric analysis showed that the impregnation improved the thermal stability of the BC films. The sheets with nanoboron nitride exhibited the best thermal stability, whereas the sheets with Firetex were determined to have the worst thermal stability. The Fourier-transform infrared spectroscopy showed some changes in the structural properties of the all BC sheets with fire retardants. As a result, it can be said that nanoboron nitride at low temperatures (25–250 °C) and Firetex and phosphoric acid at higher temperatures (600–900 °C) showed better thermal stability.

scholarly journals Optimization of cellulose nanocrystal length and surface charge density through phosphoric acid hydrolysis

2017 ◽  
Vol 376 (2112) ◽  
pp. 20170041 ◽  
Author(s):  
Oriana M. Vanderfleet ◽  
Daniel A. Osorio ◽  
Emily D. Cranston
Keyword(s):  
Thermal Stability ◽  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Charge Density ◽  
Acid Hydrolysis ◽  
Acid Concentration ◽  
Large Range ◽  
Phosphate Content ◽  
Hydrolysis Temperature ◽  
Phosphoric Acid Hydrolysis

Cellulose nanocrystals (CNCs) are emerging nanomaterials with a large range of potential applications. CNCs are typically produced through acid hydrolysis with sulfuric acid; however, phosphoric acid has the advantage of generating CNCs with higher thermal stability. This paper presents a design of experiments approach to optimize the hydrolysis of CNCs from cotton with phosphoric acid. Hydrolysis time, temperature and acid concentration were varied across nine experiments and a linear least-squares regression analysis was applied to understand the effects of these parameters on CNC properties. In all but one case, rod-shaped nanoparticles with a high degree of crystallinity and thermal stability were produced. A statistical model was generated to predict CNC length, and trends in phosphate content and zeta potential were elucidated. The CNC length could be tuned over a relatively large range (238–475 nm) and the polydispersity could be narrowed most effectively by increasing the hydrolysis temperature and acid concentration. The CNC phosphate content was most affected by hydrolysis temperature and time; however, the charge density and colloidal stability were considered low compared with sulfuric acid hydrolysed CNCs. This study provides insight into weak acid hydrolysis and proposes ‘design rules’ for CNCs with improved size uniformity and charge density. This article is part of a discussion meeting issue ‘New horizons for cellulose nanotechnology’.

Thermal stability and oil absorption of aluminum hydroxide treated by dry modification with phosphoric acid

2007 ◽  
Vol 14 (6) ◽  
pp. 779-782 ◽  
Author(s):  
Xiang-yang Zhou ◽  
Chang-lin Li ◽  
Deng-wei Huo ◽  
Jie Li ◽  
Shang-yuan Wu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Phosphoric Acid ◽  
Aluminum Hydroxide ◽  
Oil Absorption ◽  
Dry Modification
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