EN ISO 9702:1998

SLOVENSKI STANDARD
01-maj-2000
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Plastics - Amine epoxide hardeners - Determination of primary, secondary and tertiary
amine group nitrogen content (ISO 9702:1996)
Kunststoffe - Aminische Epoxidhärter - Bestimmung von primären, sekundären und
tertiären Amingruppen als Stickstoffgehalt (ISO 9702:1996)
Plastiques - Durcisseurs pour résines époxy - Détermination de la teneur en azote des
groupes amine primaire, secondaire, tertiaire (ISO 9702:1996)
Ta slovenski standard je istoveten z: EN ISO 9702:1998
ICS:
83.080.10 Duromeri Thermosetting materials
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

ISO 9702: 1996(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work of
preparing International Standards is normally carried out through IS0
technical committees. Each member body interested in a subject for
which a technical committee has been established has the right to be
represented on that committee. International organizations, governmental
and non-governmental, in liaison with ISO, also take part in the work. IS0
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard IS0 9702 was prepared by Technical Committee
ISO/TC 61, Plastics, Subcommittee SC 12, Thermosetting materials.
0 IS0 1996
All rights reserved. Unless otherwise specified, no part of this publication may be
reproduced or utilized in any form or by any means, electronic or mechanical, including
photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 CH-1211 Geneve 20 Switzerland

IS0 9702:1996(E)
INTERNATIONAL STANDARD @ IS0
Determination
- Amine epoxide hardeners -
Plastics
of primary, secondary and tertiary amine group nitrogen
content
1 Scope
RNH2 + (CH3C0)20 -+
RNHCOCH3 + CH3COOH
This International Standard specifies a method for the
determination of the primary, secondary and tertiary
amine group nitrogen content of aliphatic or aromatic
(RR’)NH + (CH3CO)zO +
amine hardeners for epoxy resins.
(RR’)NCOCH3 + CH3COOH
2 Principle
The tertiary amine group alkalinity is determined by
potentiometric titration against hydrobromic or per-
chloric acid in glacial acetic acid/acetic anhydride, as
2.1 Aliphatic amines
described by the following reaction:
2.1.1 Determination of total amine group
(RR’R”)NH + H+ + (RR’R”)NH+
nitrogen content (XT)
The total alkalinity is determined by potentiometric
The results are expressed as percentage nitrogen,
titration against hydrobromic or perchloric acid in
as described by the following
glacial acetic acid,
reactions:
2.1.3 Determination of primary amine group
nitrogen content (XLI)
RNH2 + H+ + RNH3+
The primary amine groups are reacted with a
(RR’NH + H+ -+ (RR’)NH2+
measured excess of 2,4-pentanedione (acetylacetone)
(RR’R”)N + H+ -+ (RR’R”)NH+
in A/,/V-di-methylformamide to form imines, as
described by the following reaction:
The results are expressed as percentage nitrogen.
RNH;! + CH3COCH2COCH3 --+
NOTE 1 Perchloric acid is not suitable for use with amine
CH3CNRCH2COCH3 + Hz0
hardeners such as N-aminoethylpiperazine.
The excess acetylacetone is determined by poten-
2.1.2 Determination of tertiary amine group
tiometric titration against potassium hydroxide (the
nitrogen content (X3)
reaction products of acetylacetone and primary amine
The primary and secondary amine groups are groups are neutral under these conditions).
converted into amide groups with acetic anhydride, as
described by the following reactions: The results are expressed as percentage nitrogen.

@ IS0
IS0 9702: 1996(E)
With strongly basic amines, the secondary and tertiary
2.1.4 Determination of secondary amine group
amine group alkalinity is determined by potentiometric
nitrogen content (XL~)
titration against hydrochloric acid in glacial acetic acid,
The secondary amine group nitrogen content is
as described by the following reactions:
determined by calculating the difference between the
total amine group nitrogen content and the sum of the
(ArAr’)NH + H+ -+ (ArAr’)NHz+
primary and tertiary amine group nitrogen contents.
(ArAr’Ar”) N + H+ -+ (ArAr’Ar”) N H+
22 . Aromatic amines
The results are expressed as percentage nitrogen.
2.2.1 Determination of total amine group
NOTE 2 Weakly basic amines, such as 4,4’-diamino-
nitrogen content (XT)
diphenylsulfone, are titrated with hydrobromic or perchloric
acid in glacial acetic acid.
The total alkalinity is determined by potentiometric
titration against hydrobromic or perchloric acid in
2.2.4 Determination of prim amine
glacial acetic acid, as described by the following aw group
nitrogen content &I )
reactions:
The primary amine group nitrogen content is
ArNH2 + H+ -+ ArNH3+
determined by calculating the difference between the
(ArAr’)NH + H+ -+ (ArAr’)NHz+ total amine gro Iup nitrogen content and the sum of the
secondary and tertiary amine group nitrogen contents.
(ArAr’Ar”) N + H+ -+ (ArAr’Ar”) N H+
The results are expressed as percentage nitrogen. 2.2.5 Determination of secondary amine
group
nitrogen content (XR2)
2.2.2 Determination of tertiary amine group
The secondary amine group nitrogen content is
nitrogen content (X3)
determined by calculating the difference between the
sum of the secondary and tertiary amine group
The primary and secondary amine groups are
nitrogen contents and the tertiary amine group
converted into amide groups with acetic anhydride as
nitrogen content.
described by the following reactions:
ArNH2 + (CH3CO)2O -+
3 Reagents
ArNHCOCH3 + CH3COOH
During the analysis, use only reagents of recognized
(ArAr’)NH + (CH3CO)zO --+
analytical grade and only distilled water or water of
equivalent purity.
(ArAr’)NCOCHs + CH3COOH
3.1 Acetic acid, glacial.
The tertiary amine group alkalinity is determined by
potentiometric titration against hydrobromic or
perchloric acid in glacial acetic acid/acetic anhydride,
3.2 Acetic anhydride.
as described by the following reaction.
3.3 2,4=Pentanedione (acetylacetone).
(ArAr’Ar”)N + H+ -+ (ArAr’Ar”)NH+
3.4 A/,N-diamethylformamide.
The results are expressed as percentage nitrogen.
3.5 Acetylacetone, I,5 mol/l solution in A/,Ndi-
2.2.3 Determination of the sum of the secondary
methylformamide.
and tertiary amine group nitrogen contents (X~2+3)
Dissolve 15 ml of acetylacetone (3.3) in 90 ml of
The primary amine groups are converted into Schiff
A/,/Vdimethylformamide (3.4).
bases by salicylaldehyde in glacial acetic acid, as
described by the following reaction:
3.6 Salicylaldehyde.
ArNH2 + CGH4(0H)CHO -+
3.7 Ethan-1,2-diol (ethylene glycol).
ArN=CHC&i~(Ol-l) + Hz0
0 IS0 ISO9702:1996(E)
VI is the volume, in millilitres, of the solution of
3.8 Propan-Z-01.
hydrobromic acid prepared in 3.16.1 required
to reach the end point in the titration;
3.9 Ethylene glycol/propan-2-01 mixed solvent.
V2 is the volume, in millilitres of the above
Mix 500 ml of ethylene glycol (3.7) and 500 ml of
solution (3.16.1) required in the blank test.
propan-Z-01 (3.8).
3.17 Perchloric acid, 0,l mol/l standard volumetric
3.10 Potassium hydrogen phthalate.
solution in glacial acetic acid.
3.11 Hydrobromic acid, 250 g/l solution in acetic
3.17.1 Preparation
acid.
Mix 8,5 ml of 70 % perchloric acid (or 9,9 ml of 60 %
3.12 Perchloric acid, 70 % or 60 % solution in perchloric acid) (3.12) with 500 ml of glacial acetic acid
(3.1) in a 1 000 ml b rown-glass volumetric flask (4.9).
water.
Add 30 ml (or 35 ml if 60 % perchloric acid was used)
of acetic anhydride (3.2) and mix well. Dilute to the
3.13 Potassium hydroxide.
mark with glacial acetic acid.
3.14 Hydrochloric acid, concentrated.
3.17.2 Standardization
Use the same procedure as that in 3.16.2, calculating
3.15 Sodium carbonate.
the concentration using the same equation. In this
case, cl is the concentration of the perchloric acid
3.16 Hydrobromic acid, 0,l mol/l standard volu-
solution prepared in 3.17.1.
metric solution in glacial acetic acid.
3.18 Potassium hydroxide, 0,5 mol/l standard volu-
3.16.1 Preparation
metric solution in propan-2-01.
Add 25 ml of hydrobromic acid (3.11) slowly to 100 ml
3.18.1 Preparation
of glacial acetic acid (3.1) in a 1 000 ml brown-glass
volumetric flask (4.9) and stir carefully. Dilute to the
Take 1 000 ml of propan-2-01 (3.8) in a round-bottomed
mark with glacial acetic acid.
flask and add 30 g of potassium hydroxide (3.13).
Reflux for several hours to dissolve completely. Leave
the solution in a carbon-dioxide-free atmosphere for a
3.16.2 Standardization
few days, then transfer the clear upper solution to a
polyethylene bottle and keep it in the bottle equipped
Weigh out, to the nearest 0,l mg, 0,l g to 0,2 g of
with a guard tube filled with soda lime. Take care that
potassium hydrogen phthalate (3.10) and dissolve in
the solution does not touch a cork or rubber stopper
50 ml of glacial acetic acid (3.1).
or stopper grease, which may be saponified.
Titrate this solution potentiometrically against the
solution of hydrobromic acid prepared in 3.16.1 (VI).
3.18.2 Standardization
Perform a blank test by titrating 50 ml of glacial acetic
Weigh, to the nearest 0,l mg, 0,5 g to I,0 g of
acid against the solution of hydrobromic acid prepared
potassium hydrogen phthalate (3.10) and dissolve in
in 3.16.1 (Vz).
100 ml of water.
Calculate the concentration CI of the hydrobromic acid
Titrate this solution potentiometrically against the
solution, expressed in moles of HBr per litre to the
potassium hydroxide solution prepared in 3.18.1 (V$.
nearest 0,001 mol HBr/l, using the equation
Perform a blank test separately (VJ).
1 000 x m()
Calculate the concentration ~2 of the potassium
Cl = 204,23(y - v2) hydroxide solution, expressed in moles of KOH per
litre to the nearest 0,001 mol KOH/I, using the
equation
1 OOOXrnl
of potassium
mo is the mass, in grams,
c2 = 204,23 (V3 - V’)
hydrogen phthalate used;
@ IS0
IS0 9702:1996(E)
4.3 Graduated glass cylinder, of capacity 50 ml.
where
ml is the mass, in grams, of potassium
4.4 Conical flask with ground-glass stopper, of
hydrogen phthalate used;
capacity 20 ml.
V3 is the volume, in millilitres, of the solution of
4.5 Pipette, of capacity 5 ml.
potassium hydroxide prepared in 3.18.1
required to reach the end point in the
4.6 Graduated pipette, of capacity 1 ml.
titration;
4.7 Water bath, capable of being maintained at
V4 is the volume, in millilitres, of the above
40°C.
solution (3.18.1) required in the blank test
4.8 Flasks, of capacities 100 ml, 1 000 ml and
3.19 Hydrochloric acid, 0,l mol/l standard volu-
2 000 ml.
metric solution in mixed solvent.
4.9 Graduated flasks,, capacity 1 000 ml, made of
brown glass.
3.19.1 Preparation
4.10 Potentiometric-titration apparatus, equipped
Add 1 000 ml of the ethylene glycoI/propan-2-01 mixed
with a glass-calomel electrode.
solvent (3.9) to 9 ml of concentrated hydrochloric acid
(3.14).
5 Procedure
3.19.2 Standardization
5.1 Aliphatic amines
Weigh out, to the nearest 0,l mg, 0,13 g to 0,16 g
of sodium carbonate (3.15) and dissolve in 100 ml of
of total amine group
5.1 .I Determination
water.
nitrogen content (XT)
Titrate this solution potentiometrically against the
Weigh, to the nearest 0,l mg, an amount of amine
solution of hydrochloric acid prepared in 3.19.1 (V5).
hardener containing approximately 0,001 mol of amine
group (m-r) into a 100 ml beaker (4.2). Dissolve in 50 ml
Perform a blank test separately (V&.
of glacial acetic acid (3.1). Then titrate potentio-
metrically against 0,l mol/l hydrobromic acid (3.16) or
Calculate the concentration ~3 of the hydrochloric acid
perchloric acid (3.17) (VI).
solution, expressed in moles of HCI per litre to the
nearest 0,001 mol HCI/I, using the equation
in A/-aminoethylpiperazine
Because one nitrogen
reacts only slowly with perchloric acid, it is difficult to
1 oooxm2
detect the end point. In the determination of N-amino-
c3 = 52,99 (v5 - V6)
ethylpiperazine or its derivatives, therefore, use
0,l mol/l hydrobromic acid.
Perform a blank test separately (V2) by titrating 50 ml
1122 is the mass, in grams, of sodium carbonate
of glacial acetic acid (3.1).
used;
V5 is the volume, in millilitres, of the 5.1.2 Determination of tertiary amine group
hydrochloric acid solution prepared in 3.19.1 nitrogen content (X3)
required to reach the end point in the
Weigh, to the nearest 0,l mg, an amount of amine
titration;
hardener containing approximately 0,001 mol of amine
group (~23) into a 100 ml beaker (4.2). Dissolve in 10 ml
v6 is the volume, in millilitres, of the above
solution (3.19.1) required in the blank test. of glacial acetic acid (3.1).
Add 10 ml of acetic anhydride (3.2) and mix
thoroughly. Leave at room temperature for 30 min.
4 Apparatus
Add 40 ml of glacial acetic acid (3.1) and titrate
potentiometrically against 0,l mol/l hydrobromic acid
4.1 Analytical balance, accurate to 0,l mg.
(3.16) or perchloric acid (3.17) (VI).
4.2 Beakers, of capacity 100 ml. Perform a blank test separately (V2).

@ IS0
IS0 9702: 1996(E)
5.1.3 Determination of
prim ary amine group Perform a blank test separately (
v6).
nitrogen content (XLJ )
5.2.3.2 With weakly basic aml
ines, such as 4,4’-di-
Weigh, to the nearest 0,l mg, an amount of amine
aminodiphenylsulfone, use the following procedure:
hardener containing approximately 0,002 mol of
...