TY - JOUR
T1 - Control of polymorphism and crystal size of L-glutamic acid in the absence of additives
AU - Cashell, C.
AU - Corcoran, D.
AU - Hodnett, B. K.
PY - 2004/12/17
Y1 - 2004/12/17
N2 - Slow cooling of a supersaturated solution of L-glutamic acid, with continuous or pulsed agitation during cooling, is sufficient to stabilise the α-polymorph for crystallisation times of 24 h at 45°C. Rapid cooling with agitation or slow cooling without agitation favours formation of the stable β-polymorph. A reduction in average particle size and crystal quality of the α-crystals was observed following agitation and there was a marked absence of β-inclusions on the surface of and inside the α-crystals under these conditions. Two hypotheses are presented to explain the stabilisation of the α-polymorph namely, (i) that agitation is sufficient to disrupt nucleation of the β-crystals on the surface of the α-crystals and (ii) that α-crystals formed with agitation during slow cooling are small and poorly formed and lack the necessary well-formed crystallographic facets on which the β-form can nucleate. That the β-polymorph is favoured during rapid cooling with agitation can be explained in terms of the reduced period of agitation.
AB - Slow cooling of a supersaturated solution of L-glutamic acid, with continuous or pulsed agitation during cooling, is sufficient to stabilise the α-polymorph for crystallisation times of 24 h at 45°C. Rapid cooling with agitation or slow cooling without agitation favours formation of the stable β-polymorph. A reduction in average particle size and crystal quality of the α-crystals was observed following agitation and there was a marked absence of β-inclusions on the surface of and inside the α-crystals under these conditions. Two hypotheses are presented to explain the stabilisation of the α-polymorph namely, (i) that agitation is sufficient to disrupt nucleation of the β-crystals on the surface of the α-crystals and (ii) that α-crystals formed with agitation during slow cooling are small and poorly formed and lack the necessary well-formed crystallographic facets on which the β-form can nucleate. That the β-polymorph is favoured during rapid cooling with agitation can be explained in terms of the reduced period of agitation.
KW - A1. Crystal morphology
KW - A1. Polymorphism
KW - A2. Growth from solution
KW - B1. Organic compound
KW - B2. L-glutamic acid
UR - http://www.scopus.com/inward/record.url?scp=10044288542&partnerID=8YFLogxK
U2 - 10.1016/j.jcrysgro.2004.08.020
DO - 10.1016/j.jcrysgro.2004.08.020
M3 - Article
AN - SCOPUS:10044288542
SN - 0022-0248
VL - 273
SP - 258
EP - 265
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
IS - 1-2
ER -