ASTM D4795-94(1998)

Standard Test Method for Nitrogen Content of Soluble Nitrocellulose-Alternative Method

SCOPE
1.1 Test Methods D301 for measuring nitrogen content in nitrocellulose by nitrometer are the accepted standard. However, the glassware is specialized and the precision is dependent on the development of a high level of skill by the operator. The ferrous-sulfate titration of nitrate is a classical procedure. By controlling critical variables and automating the actual titration, precision equivalent to the nitrometer can be achieved with nitrocellulose. This test method describes such a procedure.
1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 8.

General Information

• Status: Historical
• Publication Date: 09-Oct-1998
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.36 - Cellulose and Cellulose Derivatives

Relations

• Replaced By: ASTM D4795-94(2003) - Standard Test Method for Nitrogen Content of Soluble Nitrocellulose—Alternative Method
• Effective Date: 10-May-2003

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 4795 – 94 (Reapproved 1998)
Standard Test Method for
Nitrogen Content of Soluble Nitrocellulose—Alternative
Method
This standard is issued under the fixed designation D 4795; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Significance and Use
1.1 Test Methods D 301 for measuring nitrogen content in 4.1 This test method provides a simpler means for measur-
nitrocellulose by nitrometer are the accepted standard. How- ing the nitrogen content of nitrocellulose than the nitrometer
ever, the glassware is specialized and the precision is depen- described in Test Method D 301. Under controlled conditions,
dent on the development of a high level of skill by the operator. the procedure described is capable of results equivalent to
The ferrous-sulfate titration of nitrate is a classical procedure. those obtained by the nitrometer.
By controlling critical variables and automating the actual
5. Interferences
titration, precision equivalent to the nitrometer can be achieved
with nitrocellulose. This test method describes such a proce- 5.1 The presence of moisture (or other volatile components)
in the specimen will affect results. It is recommended that only
dure.
1.2 The values stated in inch-pound units are to be regarded thoroughly dry specimens be used.
5.2 Temperature rise must be controlled during the titration.
as the standard. The values given in parentheses are for
information only. The cooling bath provides that control. However, if the rate of
titrant addition is too fast, temperature may rise out of control.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the Results may then be erratic. Adherence to the procedure will
avoid temperature excursions. For optimum system efficiency,
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- room temperature should be maintained at 23 6 2°C.
5.3 The strength of the sulfuric acid used to dissolve the
bility of regulatory limitations prior to use. For specific hazard
statements, see Section 8. specimen is very important. Too low an acid strength slows the
rate of solution which, in turn, causes titrations to be abnor-
2. Referenced Documents
mally slow. Results then become erratic.
2.1 ASTM Standards:
2 6. Apparatus
D 301 Test Methods for Soluble Cellulose Nitrate
D 1193 Specification for Reagent Water 6.1 Acid Bottle Safety Dispenser.
6.2 Brinkman 20 Titration System, or equivalent, with 25
3. Summary of Test Method
mL amber buret:
3.1 A weighed specimen of nitrocellulose is dissolved in 6.2.1 Electrode, platinum.
sulfuric acid and titrated automatically with ferrous sulfate. 6.2.2 Electrode, glass.
The nitrogen content of the specimen is calculated using the 6.3 Desiccator, with drying agent.
equivalence factor of the ferrous sulfate. 6.4 Weighing bottles, 12-mL capacity, aluminum (preferred)
or glass.
6.5 Analytical Balance, accurate to 60.1 mg.
This test method is under the jurisdiction of ASTM Committee D-1 on Paint
6.6 Ovens—135°C, for drying standards, and 100°C, for
and Related Coatings, Materials, and Applications and is the direct responsibility of
drying specimens, having unexposed heating elements and the
Subcommittee D01.36 on Cellulose and Cellulose Derivatives.
Current edition approved April 15, 1994. Published June 1994. Originally door latch removed.
published as D 4795 – 88. Last previous edition D 4795 – 88.
6.7 Circulating Unit, for chilled water, 5 6 2°C.
Annual Book of ASTM Standards, Vol 06.03.
6.8 Blender, with 8-oz (0.25-L) blender jar.
Annual Book of ASTM Standards, Vol 11.01.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 4795 – 94 (1998)
7. Reagents vigorous a vortex can cause the nitrocellulose to splash onto
the sides of the beaker.
7.1 Purity of Reagents—Reagent grade chemicals shall be
10.4 With the stirrer operating and the electrodes up in the
used in all tests. Unless otherwise indicated, it is intended that
air away from the acid, slowly pour the specimen into the
all reagents shall conform to the specifications of the Commit-
vortex of the swirl. Be careful not to touch the dispensing tip
tee on Analytical Reagents of the American Chemical Society,
4 or electrodes with the weighing bottle. Reweigh the weighing
where such specifications are available. Other grades may be
bottle to find the weight of the standard by difference.
used, provided it is first ascertained that the reagent is of
10.5 Allow most of the KNO to dissolve. Visually inspect
sufficiently high purity to permit its use without lessening the 3
the solution until no more chunks or chips of KNO remain.
accuracy of the determination.
The solution may be cloudy.
7.2 Purity of Water—Unless otherwise indicated, references
10.6 Lower the electrodes and the dispensing tip into the
to water shall be understood to mean reagent water as defined
H SO .
by Type III of Specification D 1193. 2 4
10.7 Set the controls to the desired settings.
7.3 Sulfuric Acid (H SO )95to98%.
2 4
10.8 As the KNO dissolves and HNO is formed by the
7.4 Ferrous Sulfate Solution—Dissolve 350 g of ferrous 3 3
reaction of H SO and the specimen, a millivolt potential
sulfate crystals (FeSO ) in 1000 mL of distilled water. Add 2 4
change is evident by a rising recorder pen.
1000 mL of 1+1 H SO solution. Makes 2 L.
2 4
10.8.1 When the pen shows a leveling off, it is an indication
7.5 Potassium Nitrate (KNO ) Standard or an equivalent
that the majority of the KNO is in solution. Visually inspect
nitrate primary standard. 3
the solution to verify the fact that chips are no longer present.
7.6 Nitrocellulose Standard—A sample with a known nitro-
10.9 Set the buret control to a rate of about 5 mL/min. Allow
gen value or other known organic nitrate.
10 6 0.1 mL to dispense at this rate.
10.10 Stop the buret, switch the dispense-rate switch to
8. Hazards
automatic, and restart. Allow the titration to proceed automati-
8.1 Since the sample of nitrocellulose must be dried, it is
cally to the end point.
imperative that care be exercised in storage, handling, and
10.11 At the completion of the automatic titration, immedi-
disposal. Dry nitrocellulose is extremely flammable. Refer to
ately record the millilitre r
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