Thermal behavior pattern of tributyl phosphate under adiabatic conditions

Smitha, Velayuthan Sreekantan; Surianarayanan, M.; Seshadri, H.; Mandal, Asit Baran

doi:10.1007/s10973-012-2197-6

Cited by 17 publications

(8 citation statements)

References 10 publications

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“…• the reactions of red oil formation and red oil decomposition have to be clearly distinguished. • the conditions under which the red oil formation occurs have to be studied further with care and any combination that reports a lower onset temperature (such as those reported by Smitha et al (23,24), Glossop (34), and Chandran et al (35)) than the well quoted safety margin of 403 K (130 • C) should be taken seriously and never ignored. • The effect of radiolysis of the organic phase and accumulation of the radiolytic degradation products in the aqueous phase may have an accelerating effect on red oil formation and also on the decomposition behavior and have to be studied in detail.…”

Section: Discussionmentioning

confidence: 99%

“…Smitha et al (23,24) studied the thermal behavior of neat TBP under adiabatic conditions employing ARC and observed multiple exothermic activities in the temperature range 523-698K (250-425 • C). The results showed exothermic excursions, respectively at 524, 653, and 703 K (251, 380, and 430 • C) with enthalpy values of 128.2, 1348.7, and 581.8 J g −1 .…”

Section: Studies and Reviews On Red Oilmentioning

confidence: 99%

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Red Oil Excursions: A Review

Srinivasan

Rao

2014

Separation Science and Technology

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Extractants such as tri n-butyl phosphate form an explosive composition called as red oil in the presence of nitric acid under high temperatures. The formation and subsequent decomposition of red oil can lead to explosive thermal runaway conditions and is therefore, a safety concern during the spent fuel reprocessing and waste management operations. A review of the literature on the red oil excursions and related safety issues has been carried out covering the major accidents that have taken place and the literature on the red oil related studies. Other extractant systems which are also likely to undergo red oil like excursions are also covered.

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Section: Discussionmentioning

confidence: 99%

Section: Studies and Reviews On Red Oilmentioning

confidence: 99%

Red Oil Excursions: A Review

Srinivasan

Rao

2014

Separation Science and Technology

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“…The time–temperature outputs for 30 and 70 wt % TBP in n -dodecane are given in Figure . These were plotted along with the neat TBP for comparative studies. TBP, when diluted with n -dodecane at 30 and 70 wt % levels, showed different onset temperatures (239 and 443 °C).…”

Section: Results and Discussionmentioning

confidence: 99%

“…Although the conditions favorable to the thermal hazards of TBP−nitric acid system are partly available, the data on the sensitivity to thermal runaway phenomena of the chemicals involved are not available. Recently, the thermal decomposition pathway of TBP 7 and the mechanism of red oil forming reactions and the conditions which favor the formation of red oil 8 have been reported.…”

Section: Introductionmentioning

confidence: 99%

Effects of Diluents on the Reaction Hazards of Tributyl Phosphate with Nitric Acid

Sreekantan

Surianarayanan

Jala

et al. 2014

Org. Process Res. Dev.

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A proportion of 30 wt % of tributyl phosphate (TBP) in suitable diluents is the workhorse in the extraction of U and Pu in the plutonium uranium extraction (PUREX) process. Accelerating rate calorimetric (ARC) studies of effects of diluents on TBP behavior reveal a similar thermal behavior irrespective of the nature of diluents. The reactive thermal hazards of 30 wt % of TBP with 4N HNO 3 in different diluents show onset temperatures in the range of 105−130°C with a significant pressure rise. Although the onset points are closer to the operating temperature range of the PUREX process, the heat rates are small. However, the process poses pressurization hazards due to the breakdown of the structure of TBP. Oxidation of butanol to butanoic acid is the main cause for exothermic behavior in all cases.

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“…erefore, researchers studied the degradation of TBP or the thermal reaction between TBP and nitric acid. Smitha et al reported the reaction of TBP with nitric acid at different acid concentrations [12][13][14][15]; the influences of diluents on the reactions and the behaviors of heat emission were also studied previously [5,[16][17][18][19][20][21][22][23]. Nazin et al reported thermal explosions in mixtures of TBP with nitric acid [14,24].…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study on the Mechanism for the Formation of Nitro Compounds in Red Oil

Tian

Tang

et al. 2020

Journal of Chemistry

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The mechanisms involved in reactions between methane, n-hexane, n-butanol, cyclohexane, and nitric acid were explored by density functional theory calculations. All the calculations in gas phase and n-tributyl phosphate (TBP) solvent were performed at the B3LYP/6–311++G ∗ ∗ and CCSD(T)/6–311++G ∗ ∗ levels of theory. The results showed that TBP has an important effect on the reactions between nitric acid and alkanes or butanol. The reactions were considered as that the radicals (·NO2 and ·NO3 radicals are formed via the HNO3 decomposition under irradiation) initiate the H-atom depletion of the reactants (R), and the produced radicals in red oil combine with ·NO2 radical to form the nitro compounds spontaneously. The rate constants of reactions R + ·NO2 and R + ·NO3 differ substantially, the rate constants of the latter being much larger than those of the former. In the reactions of R + ·NO3, the transition states and products are 20 kJ/mol and 100 kJ/mol or more stable than the reactants, respectively, but the reactions of R + ·NO2 need to overcome energy barriers over 25 kJ/mol. The formations of products mainly depend on the reactions of R + ·NO3. For the same type of alkanes (either chain or cyclic ones), the lower the relative stabilities of carbon-centered radicals are, the more reactive the alkanes are. Cyclohexane is the most competitive species, followed by n-butanol, n-alkanes, and methane which are the least competitive.

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Thermal behavior pattern of tributyl phosphate under adiabatic conditions

Cited by 17 publications

References 10 publications

Red Oil Excursions: A Review

Red Oil Excursions: A Review

Effects of Diluents on the Reaction Hazards of Tributyl Phosphate with Nitric Acid

Theoretical Study on the Mechanism for the Formation of Nitro Compounds in Red Oil

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