|
IS0
I N T ER N AT I O N A L O R G A N I Z AT I O N FOR STAND AR D 1 ZAT I O N
IS0 RECOMMENDATION
R 914
SULPHURIC ACID AND OLEUM FOR INDUSTRIAL USE
DETERMINATION OF TOTAL NITROGEN CONTENT
Volumetric method
1 st EDIT ION
December 1968
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
---------------------- Page: 1 ----------------------
BRIEF HISTORY
The IS0 Recommendation R 914, Sulphuric acid and oleum for industrial use - Determination
of total nitrogen content - Volumetric method, was drawn up by Technical Committee ISO/TC 47,
Chemistry, the Secretariat of which is held by the Ente Nazionale Italian0 di Unificazione (UNI).
Based on detailed work on this question carried out by the Technical Committee, a Draft IS0
Recommendation was adopted in 1965.
In June 1967, this Draft IS0 Recommendation (No. 1184) was circulated to all the IS0
Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial nature, by
the following Member Bodies :
Austria
India South Africa, Rep. of
Belgium
Iran Spain
Brazil Ireland Switzerland
Chile Thailand
Italy
Cuba
Japan Turkey
Czechoslovakia
Netherlands U.A.R.
France New Zealand United Kingdom
Germany Poland U.S.S.R.
Hungary Portugal Yugoslavia
ICAITI * Romania
No Member Body opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council,
which decided, in December 1968, to accept it as an IS0 RECOMMENDATION.
Institut0 Centroamericano de Investigacion y Tecnologia Industrial (Costa Rica, Guatemala, Honduras, Nicaragua,
El Salvador, Panama).
-2-
---------------------- Page: 2 ----------------------
ISO/R 914-1968 (I
IS0 Recommendation R 914 De ce m be r 1 968
SULPHURIC ACID AND OLEUM FOR INDUSTRIAL USE
DETERMINATION OF TOTAL NITROGEN CONTENT
Volumetric method
1. SCOPE
This IS0 Recommendation describes a volumetric method for the determination of total nitrogen
content of sulphuric acid and oleum for industrial use.
2. FIELD OF APPLICATION
The method is applicable to the determination of total nitrogen content greater than 0.05
(m/m)
of sulphuric acid and oleum for industrial use.
3. PRINCIPLE
Conversion of the nitrogen present to ammonia by means of nascent hydrogen. Distillation and
absorption of ammonia by an excess of sulphuric acid standard volumetric solution and back-
titration with a sodium hydroxide standard volumetric solution in the presence of methylred-
methylene blue indicator.
4. REAGENTS
Distilled water or water of equivalent purity should be used in the test.
4.1 Devarda alloy (45 Al - 50 Cu - 5 Zn), particle size 0.2 to 0.3 mm.
4.2 Sodium hydroxide, 250 g/l solution.
4.3 Potassium permanganate, 1 O g/1 solution.
Dissolve 1 g of potassium permanganate in water and dilute to 100 ml.
4.4 Sulphuric acid, 0.1 N standard volumetric solution (see Note, section 7).
4.5 Sodium hydroxide, 0.1 N standard volumetric solution (see Note, section 7).
-3-
---------------------- Page: 3 ----------------------
ISO/R 914-1968 (
4.6 Mixed indicator, ethanolic solution.
Dissolve 0.1 g of methylred in 50 ml of 95 (v/v) ethanol, add 0.05 g of methylene blue and
dilute to 100 ml with the same ethanol.
4.7 Litmus paper (red).
5. APPARATUS
Ordinary laboratory apparatus and
Weighing bottle, ground glass stoppered, capacity approximately 60 ml.
5.1
5.2 Distillation apparatus (see Figure opposite) with ground glass joints.
6. PROCEDURE
6.1 Test portion and preparation of sample solution
Fill weighing bottle (5.1) with the test sample and weigh by difference,to the nearest 10 mg, a
test portion of approximately 50 g.
Cooling to ensure that the temperature is kept below 40 OC, slowly pour the test portion onto
crushed ice contained in a beaker of sui
...