scholarly journals Mathematical Modeling of Urea Reaction with Sulfuric Acid and Phosphoric Acid to Produce Ammonium Sulfate and Ammonium Dihydrogen Phosphate Respectively

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8004
Author(s):  
Juan Carlos Beltrán-Prieto ◽  
Karel Kolomazník
Keyword(s):  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Ammonium Sulfate ◽  
Organic Fertilizer ◽  
Reaction Rates ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
Acid Media ◽  
Safe Handling ◽  
Full Conversion

Urea is the final product of protein metabolism in mammals and can be found in different biological fluids. Use of mammalian urine in agricultural production as organic fertilizer requires safe handling to avoid the formation of ammonia that will decrease the fertilizer value due to the loss of nitrogen. Safe handling is also required to minimize the decomposition of urea into condensed products such as biuret and cyanuric acid, which will also have a negative impact on the potential sustainable production of crops and sanitation technologies. The study of thermodynamics and reaction kinetics of urea stabilization plays a key role in understanding the conditions under which undesirable compounds and impurities in urea-based fertilizers and urea-based selective catalytic reduction systems are formed. For this reason, we studied the reaction of urea in acid media to achieve urea stabilization by modeling the reaction of urea with sulfuric acid and phosphoric acid, and estimating the reaction enthalpy and adiabatic heat difference for control of the heat released from the neutralization step using Ca(OH)2 or MgO for the safety of the process. Numerical and simulation analyses were performed by studying the effect of the surrounding temperature, the ratio of acid reagent to urea concentration, the rate of addition, and the reaction rate to estimate the required time to achieve an optimum value of urea conversion into ammonium dihydrogen phosphate or ammonium sulfate as potential technological opportunities for by-product valorization. Full conversion of urea was achieved in about 10 h for reaction rates in the order of 1 × 10−5s−1 when the ratio of H2SO4 to CH4N2O was 1.5. When increasing the ratio to 10, the time required for full conversion was considerably reduced to 3 h.

scholarly journals Antipyrene preparation based on phosphoric acid with carbamide

2020 ◽  
Vol 3 (10) ◽  
pp. 292-299
Author(s):  
Olimova Mohinur Karimjon qizi
Keyword(s):  
Phosphoric Acid ◽  
Orthophosphoric Acid ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
Fire Retardants ◽  
Nitrogen And Phosphorus ◽  
Phosphorus Containing

In this work, we have carried out research on the synthesis of nitrogen and phosphorus-containing fire retardants. Epichlorohydrin, urea, melamine, ammonium dihydrogen phosphate, orthophosphoric acid, morpholine were selected as objects of research

scholarly journals Mass transfer process study of Fe(III) extraction from ammonium dihydrogen phosphate solution

2020 ◽  
Vol 85 (8) ◽  
pp. 1055-1065
Author(s):  
Weiqi Li ◽  
Hui Liu ◽  
Jun Li ◽  
Caixia You ◽  
Jianhong Luo ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Mass Transfer Process ◽  
Dihydrogen Phosphate ◽  
Phosphate Solution ◽  
Ammonium Dihydrogen Phosphate ◽  
Extraction Mechanism ◽  
Wet Process ◽  
Industrial Grade ◽  
Map Solution ◽  
Kinetics Of

The crystallization of ammonium dihydrogen phosphate (MAP) is largely affected by certain metal ions such as Fe (III), and the influence seems to be pointed at both ends. Therefore, the industrial-grade MAP products can only be obtained by purifying the neutralized MAP solution from wet-process phosphoric acid (WPA). The extraction kinetics of Fe (III) from MAP solution using di-2-ethylhexyl phosphoric acid (D2EHPA) in sulfonated kerosene measured by the Lewis cell. The extraction mechanism is discussed and confirmed on the basis of the dimeric model of D2EHPA in non-polar solution. From the temperature dependence of reaction rate, the value of Ea and Kf are calculated and the extraction regimes are deduced to be mixed controlled with diffusion and chemical reaction for Fe (III). Ultimately, the rate equation for the extraction reaction of Fe (III) with D2EHPA is obtained as follows: Rf = 0.028cFe3+1.2cH2A2 0.81cH+-0.85.

scholarly journals Moisture Resistance, Thermal Stability and Fire Behavior of Unsaturated Polyester Resin Modified with L-histidinium Dihydrogen Phosphate-Phosphoric Acid

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 932
Author(s):  
Kamila Sałasińska ◽  
Maciej Celiński ◽  
Kamila Mizera ◽  
Mateusz Barczewski ◽  
Paweł Kozikowski ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Polyester Resin ◽  
Unsaturated Polyester ◽  
Fire Behavior ◽  
Fire Retardant ◽  
Thermomechanical Properties ◽  
Unsaturated Polyester Resin ◽  
Dihydrogen Phosphate ◽  
Smoke Emission ◽  
Volatile Products

In this paper, the fire behavior of unsaturated polyester resin (UP) modified with L-histidinium dihydrogen phosphate-phosphoric acid (LHP), being a novel intumescent fire retardant (IFR), was investigated. Thermal and thermomechanical properties of the UP with different amounts of LHP (from 10 to 30 wt. %) were determined by thermogravimetric analysis (TG) as well as dynamic mechanical thermal analysis (DMTA). Reaction to small flames was studied by horizontal burning (HB) test, while fire behavior and smoke emission were investigated with the cone calorimeter (CC) and smoke density chamber. Further, the analysis of volatile products was conducted (TGA/FT-IR). It was observed that the addition of LHP resulted in the formation of carbonaceous char inhibiting the thermal decomposition, burning rate and smoke emission. The most promising results were obtained for the UP containing 30 wt. % of LHP, for which the highest reduction in maximum values of heat release rate (200 kW/m2) and total smoke release (3535 m2/m2) compared to unmodified polymer (792 kW/m2 and 6895 m2/m2) were recorded. However, some important disadvantage with respect to water resistance was observed.

Study of Vibrational Spectra of Polyaniline Doped with Sulfuric Acid and Phosphoric Acid

2001 ◽  
Vol 96 (1-3) ◽  
pp. 173-182 ◽  
Author(s):  
Manju Arora ◽  
Vandna Luthra ◽  
Ramadhar Singh ◽  
S K Gupta
Keyword(s):  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Vibrational Spectra

Properties of CMV cation exchange membranes in sulfuric acid media

2006 ◽  
Vol 284 (1-2) ◽  
pp. 67-78 ◽  
Author(s):  
Le Xuan Tuan ◽  
M. Verbanck ◽  
C. Buess-Herman ◽  
H.D. Hurwitz
Keyword(s):  
Sulfuric Acid ◽  
Cation Exchange ◽  
Acid Media

scholarly journals Ureido Functionalization through Amine-Urea Transamidation under Mild Reaction Conditions

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1583
Author(s):  
Natalia Guerrero-Alburquerque ◽  
Shanyu Zhao ◽  
Daniel Rentsch ◽  
Matthias M. Koebel ◽  
Marco Lattuada ◽  
...  
Keyword(s):  
Aqueous Media ◽  
Reaction Times ◽  
Reaction Rates ◽  
Secondary Amines ◽  
Isocyanic Acid ◽  
Advantages And Disadvantages ◽  
Major Disadvantage ◽  
Wide Range ◽  
Potential Alternative ◽  
Full Conversion

Ureido-functionalized compounds play an indispensable role in important biochemical processes, as well as chemical synthesis and production. Isocyanates, and KOCN in particular, are the preferred reagents for the ureido functionalization of amine-bearing compounds. In this study, we evaluate the potential of urea as a reagent to graft ureido groups onto amines at relatively low temperatures (<100 °C) in aqueous media. Urea is an inexpensive, non-toxic and biocompatible potential alternative to KOCN for ureido functionalization. From as early as 1864, urea was the go-to reagent for polyurea polycondensation, before falling into disuse after the advent of isocyanate chemistry. We systematically re-investigate the advantages and disadvantages of urea for amine transamidation. High ureido-functionalization conversion was obtained for a wide range of substrates, including primary and secondary amines and amino acids. Reaction times are nearly independent of substrate and pH, but excess urea is required for practically feasible reaction rates. Near full conversion of amines into ureido can be achieved within 10 h at 90 °C and within 24 h at 80 °C, and much slower reaction rates were determined at lower temperatures. The importance of the urea/amine ratio and the temperature dependence of the reaction rates indicate that urea decomposition into an isocyanic acid or a carbamate intermediate is the rate-limiting step. The presence of water leads to a modest increase in reaction rates, but the full conversion of amino groups into ureido groups is also possible in the absence of water in neat alcohol, consistent with a reaction mechanism mediated by an isocyanic acid intermediate (where the water assists in the proton transfer). Hence, the reaction with urea avoids the use of toxic isocyanate reagents by in situ generation of the reactive isocyanate intermediate, but the requirement to separate the excess urea from the reaction product remains a major disadvantage.

The Effect of Phosphatic Composite on Magnesium Phosphate Cement Performance

2014 ◽  
Vol 809-810 ◽  
pp. 477-484
Author(s):  
Zhao Qing Qi ◽  
Hong Tao Wang ◽  
Jun Liang Dang ◽  
Shi Hao Zhang ◽  
Jian Hua Ding
Keyword(s):  
Setting Time ◽  
Potassium Dihydrogen Phosphate ◽  
Magnesium Phosphate ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
Hydrogen Phosphate ◽  
Sodium Dihydrogen Phosphate ◽  
Disodium Hydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
Sodium Dihydrogen

The capacity of 10%, 30%, and 50% ammonium dihydrogen phosphate were replaced with an equal amount of three phosphate (potassium dihydrogen phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate) respectively. Magnesium phosphate cement was made by phosphate of replaced, which strength, setting time, fluidity, hydration temperature, and the hydration products was researched. The results show that: MPC was made that replaced with the equal amount of three kind of phosphate, which has good mechanical properties. Setting time and fluidity change along with the replacment. Three kind of phosphate replace ammonium dihydrogen phosphate, which change the hydration process of MPC. When ammonium dihydrogen phosphate was replaced by an equal amount of disodium hydrogen phosphate, the temperature of hydration is only 69.4 °C. XRD showed that the diffraction peaks of composite’s magnesium phosphate cement increases.

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