US 10,590,153 B2Granted

Process for producing crystalline DTPMP

AssigneeZschimmer & Schwarz Mohsdorf GmbH & Co. KG

InventorsThomas Kreher, Stephan Liebsch, Carsten Rudolph

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Abstract

The present invention relates to crystallizates of the pure aminoalkylenephosphonic acid DTPMP in three crystal polymorphs and to a process for obtaining solid crystalline DTPMP by a preferably one-stage crystallization from an aqueous product mixture comprising DTPMP, wherein the process comprises the following process steps: (a) introducing seed crystals comprising DTPMP into an aqueous crude product comprising DTPMP with a total proportion in the range from 10 to 65 percent by mass up to a suspension density in the range from 1% to 25%; (b) introducing kinetic energy into the aqueous crude product to precipitate a crystallizate containing DTPMP as pure acid with a total content of at least 75% by mass; and (c) removing the crystallizate formed from the aqueous crude product by sedimentation and/or filtration, such that DTPMP is obtained as a solid end product in the form of a crystallizate.

Claims11

Dependent claims

Crystallisate of the pure acid diethylenetriamine penta(methylenephosphonic acid) (DTPMP) of the general formula (I) or a tautomeric form thereof:

wherein n is a number between 0 and 2, and
wherein the crystallisate has at least one crystal modification selected from α, β and γ,
wherein the α crystal modification comprises the following characteristic reflections in the X-ray diffraction diagram, measured with Cu-Kα radiation:
2Θ
d
6.8
13.00
17.9
5.0
20.2
4.40
22.2
4.00
22.5
3.95
23.0
3.86
23.1
3.84
25.0
3.6.
wherein the β crystal modification comprises the following characteristic reflections in the X-ray diffraction diagram, measured with Cu-Kα radiation:
2Θ
d
6.7
13.17
18.6
4.77
19.6
4.5
20.0
4.4
22.1
4.0
22.5
3.9
23.0
3.9
24.8
3.6
25.2
3.5,
and
wherein the γ crystal modification comprises the following characteristic reflections in the X-ray diffraction diagram, measured with Cu-Kα radiation:
2Θ
d
13.0
6.8
17.9
4.9
22.0
4.0
22.4
4.0
23.1
3.8
23.3
3.8
25.1
3.6
26.1
3.4.

59 more elements

Dependencies are inferred from the claim text.