Phosphoric Acids and Phosphates

Gilmour, Rodney

doi:10.1002/0471238961.1608151907011804.a01.pub3

Cited by 4 publications

(3 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is well documented that phosphoric acid can be present as various types of monomeric and oligomeric species in an aqueous solution where the distribution is highly dependent on the concentration of phosphoric acids (or counted as P 2 O 5 ) in the solution. ,, As phosphoric acid becomes concentrated, it is shown to not only increase the quantity of orthophosphoric acid but also to drive oligomerization of phosphoric acid to polyphosphoric acid. The polyphosphoric acid acts as a strong acid because more protons can be released from polyphosphoric acid stabilized by tautomerization and delocalization of negative charge in the structure, eventually greatly increasing the acidity of the solution.…”

Section: Resultsmentioning

confidence: 99%

Green Manufacturing of Silyl-Phosphate for Use in 3D NAND Flash Memory Fabrication

Lee

Kim

Tikue

et al. 2021

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

Three-dimensional NAND flash memory featuring dozens of vertically stacked memory cells is the state-of-the-art technology for most storage platforms. To fabricate threedimensional (3D) NAND memory, lateral etching of the Si 3 N 4 layer over SiO 2 is an essential step that is conducted through a wet etching process using a phosphoric acid-based etchant. Silylphosphate or highly selective nitride serves as an etching solution additive to control the SiO 2 layer dissolution rate. However, silylphosphate is prepared with an expensive monomeric silica precursor and at high reaction temperatures and generates environmentally harmful byproduct gases, such as HCl, HF, and CH 3 OH. This study demonstrates that silyl-phosphate can be prepared using low-cost polymeric silica under a mild reaction temperature by changing the characteristic acidity of phosphoric acid. The possibility of tuning the phosphoric acid acidity was first studied by molecular dynamics simulations, and phosphoric acids with stronger acidity were prepared by the evaporation of water from H 3 PO 4 (85%). The concentrated phosphoric acid enabled a fast reaction of polymeric silica and phosphate at a low reaction temperature (80 °C). The obtained silyl-phosphate lowered the SiO 2 layer dissolution rate, thereby yielding a Si 3 N 4 /SiO 2 layer etching ratio of up to 940. The proposed method offers an environmentally friendly production process for special chemicals used in 3D NAND flash memory fabrication. KEYWORDS: 3D NAND, concentrated H 3 PO 4 , fumed silica, Si 3 N 4 layer, SiO 2 layer, wet etching

show abstract

Section: Resultsmentioning

confidence: 99%

Green Manufacturing of Silyl-Phosphate for Use in 3D NAND Flash Memory Fabrication

Lee

Kim

Tikue

et al. 2021

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

show abstract

“…Phosphates would be a finite resource. Around 1850, the introduction of phosphates in food was associated with the development of synthetic phosphate fertilizers in the United States (Gilmour, 2019). There are major environmental issues, especially water pollution, resulting from the widespread use of phosphate‐based fertilizers, due to excessive growth of algae and oxygen depletion in lakes.…”

Section: Environmental and Health Issuesmentioning

confidence: 99%

Inventions on phosphates for chemical leavening

Gélinas

2022

Int J of Food Sci Tech

View full text Add to dashboard Cite

Summary Baking powders contain leavening acids that activate gas‐releasing agents such as sodium bicarbonate. This is a review of the patent literature on phosphate‐based leavening acids developed between 1856 and 2019. Overall, 174 patented inventions were found on 28 phosphate‐based compounds, which corresponded to more than half of the inventions disclosed on leavening acids. Inventors had a strong interest in monocalcium phosphate, sodium acid pyrophosphate and, to a lesser extent, sodium aluminium phosphate and miscellaneous acid phosphates. As cheap alternatives to tartrates, most early phosphate‐based leavening acids were difficult to keep because they had a high affinity for moisture and tended to react prematurely with gas‐releasing agents in baking powders. The evolution of phosphates in chemical leavening reflected changes in the consumption of bakery foods, especially in the United States where chemical leavening has been very popular for food preparations like prepared flours, ready‐to‐use bakery mixes and refrigerated doughs. Sodium‐free phosphates are solutions to reduce salt intake in food. Alternatives to phosphates are searched due to potential health issues.

show abstract

“…Phosphoric acid is industrially manufactured from phosphate rock in two main ways: thermal or wet processes [2]. The thermal process enables the production of high-quality phosphoric acid, but at a very significant energy cost and with severe environmental Materials 2023, 16, 6228 2 of 20 impacts [3].…”

Section: Introductionmentioning

confidence: 99%

Removal of Organic Matter from Tunisian Industrial Phosphoric Acid by Adsorption onto Purified Natural Illite/Kaolinite Clay: Kinetics, Isothermal and Thermodynamic Studies

Oueriemi,

Ben Amor,

Hassen

et al. 2023

Materials

View full text Add to dashboard Cite

This work aims to use a green, economical and efficient adsorbent to remove organic matter from Tunisian industrial wet phosphoric acid (WPA: 52% P2O5). For this purpose, a natural and abundant clay is extracted from the Douiret, Tataouine deposit in southern Tunisia. This clay is being tested for the first time as an adsorbent in WPA medium. The raw clay and purified clay are analysed using standard analytical techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, and BET methods. The results show that the raw clay is a mixture of illite and kaolinite, with other mineral impurities, mainly quartz. Organic matter adsorption tests show that the purified clay exhibits greater effectiveness than raw clay. The parametric study with purified clay indicates that temperature, contact time, and clay dosage strongly influence organic matter adsorption. The highest adsorption occurs at 60 °C after 50 min, reaching 56% with 8 g of purified clay per kg of WPA. Among several recognised models, the pseudo-second-order kinetic model and the Sips isotherm model are the most suitable for modelling the experimental data. This study suggests that Douiret clay can be considered an effective, inexpensive and environmentally friendly adsorbent for eliminating organic matter in industrial phosphoric acid.

show abstract

Phosphoric Acids and Phosphates

Cited by 4 publications

References 21 publications

Green Manufacturing of Silyl-Phosphate for Use in 3D NAND Flash Memory Fabrication

Green Manufacturing of Silyl-Phosphate for Use in 3D NAND Flash Memory Fabrication

Inventions on phosphates for chemical leavening

Removal of Organic Matter from Tunisian Industrial Phosphoric Acid by Adsorption onto Purified Natural Illite/Kaolinite Clay: Kinetics, Isothermal and Thermodynamic Studies

Contact Info

Product

Resources

About