Evidence for a fragmentation mechanism during the formation of calcium carbonate organo-nano-particles

Cunningham, Ian D.; Courtois, Jean-Philippe; Danks, Timothy N.; Heyes, D. M.; Moreton, David; Taylor, Spencer E.

doi:10.1016/j.colsurfa.2006.12.052

Cited by 5 publications

(8 citation statements)

References 26 publications

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“…In many cases, Ca(OH) 2 was solely utilized to simplify the reaction [11,12,14], however it suffered from the disadvantage that excessive solid wastes produced in the crude reaction products. So it was advantageous in industrial practice to employ a mixture of Ca(OH) 2 and CaO as the reserve alkaline agents to improve lime utilization and reduce the products viscosity [33,[51][52][53].…”

Section: Alkaline Calcium Saltmentioning

confidence: 99%

“…The early model brought by Marsh and Paley proposed that metal carbonate small particles precipitated out of the solution by reaction of soluble metal intermediates with the dissolved carbon dioxide gas [11], while the existence of soluble intermediates has never been testified and it cannot explain the situation that particles of different size can be readily produced with slight modifications of the experimental conditions employing the same surfactant. A second model attributed the generation of colloidal particles to the direct carbonation of macroscopic calcium hydroxide particles stabilized by surfactants, and recently, a fragmentation process was suggested to be responsible for the rapid reduction in particle size during the carbonation of calcium hydroxide in a hexadecane suspension in the presence of calixarene and stearic acid as stabilizers [12]. The most acceptable model for carbonation is proposed to involve CaCO 3 particle nucleation and growth within reverse micelles [11,13,14], setting a practical example for surfactant-templated nanomaterials synthesis [15] analogs to reaction in water-in-oil (w/o) microemulsion nanoreactors [16].…”

Section: Introductionmentioning

confidence: 98%

“…It is possible to discern the more detailed structure and composition of overbased nanodetergents by virtue of adopting modern analytical techniques such as dynamic light scattering (DLS) [17], scanning/ transmission electron microscopy (SEM/TEM) [18,19], FTIR [20], nuclear magnetic resonance (NMR) [12,17], and small angle Xray and neutron scattering (SAXS/SANS) [21]. Besides, theoretical calculation and modeling have been developed to simulate the process and predict the morphological parameters (size and shape) of the colloidal particles [13,[22][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Calcium carbonate phase transformations during the carbonation reaction of calcium heavy alkylbenzene sulfonate overbased nanodetergents preparation

Chen

Xiao

Chen

et al. 2011

Journal of Colloid and Interface Science

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Section: Alkaline Calcium Saltmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Calcium carbonate phase transformations during the carbonation reaction of calcium heavy alkylbenzene sulfonate overbased nanodetergents preparation

Chen

Xiao

Chen

et al. 2011

Journal of Colloid and Interface Science

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“…Alkaline calcium salts including calcium oxide and/or calcium hydroxide were adopted to produce the colloidal particles of calcium carbonate for overbased detergent preparation. 2 Sometimes Ca(OH) 2 was exclusively utilized to simplify the reaction; 7,29,33 however, it suffered from the disadvantage that excessive solid wastes were generated in the crude reaction products. Thus industrial practice is to employ a mixture of Ca(OH) 2 and CaO as the alkaline calcium salt reagents to improve lime utilization and reduce the viscosity of the products.…”

Section: Thermal Stability Assessment Of Calcabs and Caslabsmentioning

confidence: 99%

Universal Phase Transformation Mechanism and Substituted Alkyl Length and Number Effect for the Preparation of Overbased Detergents Based on Calcium Alkylbenzene Sulfonates

Chen

2013

Ind. Eng. Chem. Res.

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Overbased calcium sulfonate is one of the largest commercially produced nanomaterials; the phase transformation mechanism involved in the key process of carbonation reaction for overbased detergent preparation has not yet been fully understood. Following our previous investigation based on the heavy alkylbenzene sulfonate (HABS) surfactant of industrial byproduct, two commercial products with well-defined chemical compositions and structures, long-chain alkylbenzene sulfonate (LCABS) and comparative short-chain linear alkylbenzene sulfonate (SLABS), are employed in this study as model surfactants for further mechanism study of this pivotal process by the combination of analytical techniques such as potentiometric titration, DLS, TEM, FTIR, and XRD. It has been demonstrated that amorphous calcium carbonate (ACC) is a prerequisite for the preserving and stabilization of the alkaline reserve, especially under thermal work environment. The phase transformation from ACC to crystalline vaterite polymorph rather than calcite has been unambiguously confirmed as a universal mechanism for all the alkylbenzene sulfonate based systems. Furthermore, the length and number of alkyl tails of alkylbenzene sulfonate surfactants exhibit a strong influence on characteristics of detergent products. The LCABS with long-chain alkyl substituents or HABS with dialkyl substituents plays an important role not only in inhibiting the agglomeration process, but also in protecting the metastable inorganic cores from fusion to avoid phase transformation. Such understanding should be of crucial importance for guiding the preparation of overbased detergents and greases. In addition, the study on the influence of the molar ratio of calcium oxide in the total alkaline calcium salts and the dosage of surfactant LCABS, promoter methanol, and catalyst anhydrous calcium chloride help to determine the suitable work window for detergent production, and moreover, the water content provides a handle for better understanding the reaction process and achieving good quality control for detergent manufacturing.

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“…It is this region that interacts with and makes the nanoparticle soluble in the engine oil. Typical synthetic procedures and characterization of the overbased product are described in refs and .…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Studies of Overbased Detergents on a Water Surface

et al. 2017

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Molecular dynamics (MD) simulations are reported of model overbased detergent nanoparticles on a model water surface which mimic their behavior on a Langmuir trough or large water droplet in engine oil. The simulations predict that the structure of the nanoparticle on a water surface is different to when it is immersed in a bulk hydrophobic solvent. The surfactant tails are partly directed out of the water, while the carbonate core maximizes its extent of contact with the water. Umbrella sampling calculations of the potential of mean force between two particles showed that they are associated with varying degrees with a maximum binding free energy of ca. 10 kT for the salicylate stabilized particle, ca. 8 kT for a sulfurized alkyl phenate stabilized particle, and ca. 5 kT for a sulfonate stabilized particle. The differences in the strength of attraction depend on the proximity of nearest approach and the energy penalty associated with the disruption of the hydration shell of water molecules around the calcium carbonate core when the two particles approach. This is greatest for the sulfonate particle, which partially loses the surfactant ions to the solution, and least for the salicylate, which forms the weakest water "cage". The particles are separated by a water hydration layer, even at the point of closest approach.

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Evidence for a fragmentation mechanism during the formation of calcium carbonate organo-nano-particles

Cited by 5 publications

References 26 publications

Calcium carbonate phase transformations during the carbonation reaction of calcium heavy alkylbenzene sulfonate overbased nanodetergents preparation

Calcium carbonate phase transformations during the carbonation reaction of calcium heavy alkylbenzene sulfonate overbased nanodetergents preparation

Universal Phase Transformation Mechanism and Substituted Alkyl Length and Number Effect for the Preparation of Overbased Detergents Based on Calcium Alkylbenzene Sulfonates

Molecular Dynamics Studies of Overbased Detergents on a Water Surface

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