Growth promoting effect of organic impurities on growth kinetics of KAP and KDP crystals

Кузнецов, В. А.; Okhrimenko, T. M.; Rak, Mirosława

doi:10.1016/s0022-0248(98)00489-8

Cited by 91 publications

(69 citation statements)

References 8 publications

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“…However, some impurities can promote crystal growth, which was called the catalytic effect of additives. This effect was observed in the presence of organic as well as inorganic additives [6,7]. With increasing additive concentration, the impurity leads to first an increase and then a decrease in the growth rate, passing through a maximum.…”

Section: Introductionmentioning

confidence: 86%

In situ measurement of growth kinetics of {100} KDP crystal faces in the presence of polyphosphate impurities

Liu¹,

Fang

Wang

et al. 2008

Cryst. Res. Technol.

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The face growth rate and critical supersaturation of {100} face were in situ measured using the laserpolarization-interference technique in the presence of potassium pyrophosphate, trimetric sodium phosphate and sodium hexametaphosphate impurities. The polyphosphate impurities inhibit the growth rate of prismatic faces. The face growth rate as a function of supersaturation at different impurity concentrations, as well as critical supersaturation as a function of impurity concentrations, was found in good agreement with a twodimensional nucleation model in the pure system and Kubota and Mullin's model in the presence of impurities. The average distance L between active sites available for impurity adsorption as well as the edge free energy was calculated.

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Section: Introductionmentioning

confidence: 86%

In situ measurement of growth kinetics of {100} KDP crystal faces in the presence of polyphosphate impurities

Liu¹,

Fang

Wang

et al. 2008

Cryst. Res. Technol.

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“…The same research group also used HPMC to nucleate amorphous flutamide [14] and several other polymeric additives to inhibit growth of ritonavir [35][36][37]. In some cases polymers can promote growth: in particular, it was found that a very small amount of ethylene dinitrotetraacetic acid disodium salt (EDTA) could accelerate the growth of potassium dihydrogen phosphate (KDP) crystals by forming molecular complexes with adventitious impurities in solution and eliminating their inhibiting effect [38]. Recently, a mathematical description of the effect of one or more additive on the shape of KDP crystals was developed using population balance equations with the purpose of controlling the shape of the produced crystals [6] [7].…”

Section: Introductionmentioning

confidence: 99%

A study on the effect of the polymeric additive HPMC on morphology and polymorphism of ortho-aminobenzoic acid crystals

Simone

Cenzato

Nagy

2016

Journal of Crystal Growth

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Citation: SIMONE, E., CENZATO, M. and NAGY, Z., 2016. A study on the effect of the polymeric additive HPMC on morphology and polymorphism of ortho-aminobenzoic acid crystals. Journal of Crystal Growth, 446, Additional Information:• This paper was accepted for publication in the journal Journal of AbstractIn the present study, the effect of Hydroxy Propyl Methyl Cellulose (HPMC) on the crystallization of ortho-aminobenzoic acid (OABA) was investigated by seeded and unseeded cooling crystallization experiments. The influence of HPMC on the induction time, crystal shape of Forms I and II of OABA and the polymorphic transformation time was studied.Furthermore, the capability of HPMC to inhibit growth of Form I was evaluated quantitatively and modelled using population balance equations (PBE) solved with the method of moments. The additive was found to strongly inhibit nucleation and growth of Form I as well as to increase the time for the polymorphic transformation from Form II to I.Solvent was also found to influence the shape of Form I crystals at equal concentrations of HPMC. In situ process analytical technology (PAT) tools, including Raman spectroscopy, focused beam reflectance measurement (FBRM) and attenuated total reflectance (ATR) UVVis spectroscopy were used in combination with off-line techniques, such as optical microscopy, scanning electron microscopy (SEM), Raman spectroscopy, MalvernMastersizer and differential scanning calorimetry (DSC) to study the crystals produced. The results illustrate how shape, size and stability of the two polymorphs of OABA can be controlled and tailored using a polymeric additive.

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“…However, the adsorption mechanism and the growth interruption mechanism by these metal ions have not been completely understood. Several studies about the effect of EDTA (Ethylene-Diamine-Tetraacetic-Acid, C 10 H 16 N 2 O 8 ) on crystal growth have been reported [8][9][10][11][12][13][14]. When only EDTA exists in the solution as an impurity against the crystal growth of KDP, the agent spreads the metastable zone and increases the growth rate about 1.5 times.…”

Section: Introductionmentioning

confidence: 99%

Experimental and theoretical study of recovery mechanism of impurity effect by the addition of EDTA

Asakuma¹,

Nishimura

Kimura

et al. 2007

Cryst. Res. Technol.

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The impurity effect by trivalent metal ion such as Al 3+ , Fe 3+ and Cr 3+ during crystal growth of KDP is reasonably well documented. If a metal ion is adsorbed onto the crystal surface, it prevents the step propagation relevant to the crystal growth rate. However, this impurity adsorption mechanism is still not well understood. Recently, in our work on the addition of chelate agents, a recovery effect of the metal ion adsorption was discovered. However, its recovery mechanism is not clearly understood both theoretically and phenomenally. In this research, ethylene-diamine-tetra-acetic acid, EDTA, which is the most common chelate agent, was used as a recovery agent. The recovery mechanism was considered from the correlation of experimental data and the interfacial distribution model that we proposed in our former study. Furthermore, quantum calculation of EDTA metal complex can explain the relaxation of impurity adsorption by the addition of EDTA.

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Growth promoting effect of organic impurities on growth kinetics of KAP and KDP crystals

Cited by 91 publications

References 8 publications

In situ measurement of growth kinetics of {100} KDP crystal faces in the presence of polyphosphate impurities

In situ measurement of growth kinetics of {100} KDP crystal faces in the presence of polyphosphate impurities

A study on the effect of the polymeric additive HPMC on morphology and polymorphism of ortho-aminobenzoic acid crystals

Experimental and theoretical study of recovery mechanism of impurity effect by the addition of EDTA

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