Benzyl Alcohol
C7H8O 108.1
Phenylmethanol
[100-51-6].
(ben' zil al' ka hol).
| Attributes | EP | JP | USP |
|---|---|---|---|
| Definition | + | + | + |
| Refractive Index | + | + | + |
| Acidity | + | + | + |
| Benzaldehyde and Other Related Substances | + | + | + |
| Peroxide Value | + | + | + |
| Residue on Evaporation | + | + | + |
| Assay | + | + | + |
Legend: + will adopt and implement; 
will not stipulate.
will not stipulate.
Nonharmonized attributes: Characters, Clarity of Solution, Color of Solution, Labeling, and Packaging and Storage
Local attributes: Identification (IR) (USP), Reference Standards (USP)
Reagents and Reference materials: Each pharmacopeia will adapt the text to take account of local reference materials and reagent specifications.
+'&img=../../images/v35300/cas-100-51-6.gif&casNumber=100-51-6&usp=35&nf=30&chemicalStructureImage=true&ID='+parent.myID,600,500);)
C7H8O 108.1
Phenylmethanol
[100-51-6].DEFINITION
Benzyl Alcohol contains NLT 98.0% and NMT the equivalent of 100.5% of phenylmethanol (C7H8O).
IDENTIFICATION
• 
Infrared Absorption 
197F
:
On undried specimen
Infrared Absorption 197F:
On undried specimen
ASSAY
• Procedure
Phenolphthalein solution:
Dissolve 0.1 g of phenolphthalein in 80 mL of ethanol (96%), and dilute with water to 100.0 mL. To test for sensitivity, add 100 mL of carbon dioxide-free water to 0.1 mL of the Phenolphthalein solution. The solution is colorless. NMT 0.2 mL of 0.02 M sodium hydroxide is required to change the color to pink.
Sample:
0.900 g
Analysis:
To the Sample add 15 mL of a freshly prepared mixture of pyridine and acetic anhydride (7:1), and boil under a reflux condenser on a water bath for 30 min. Cool, and add 25 mL of water. Using 0.25 mL of Phenolphthalein solution as the indicator, titrate with 1 M sodium hydroxide VS. Carry out a blank titration. Calculate the percentage content of C7H8O:
Result = 10.81 × (n1 n2)/m
n2)/m| n2 | = | = amount of 1 M sodium hydroxide used for the sample (mL) |
| n1 | = | = amount of 1 M sodium hydroxide used for the blank (mL) |
| m | = | = amount of sample taken (g) |
Acceptance criteria:
98.0%–100.5%
IMPURITIES
Inorganic Impurities
• Residue on Evaporation
Analysis:
After ensuring that the Benzyl Alcohol complies with the test for Fats and Fixed Oils, Peroxide Value, evaporate 10.0 g to dryness in a tared quartz or porcelain crucible or platinum dish on a hot plate at a temperature not exceeding 200
. Ensure that the Benzyl Alcohol does not boil during evaporation. Dry the residue on the hot plate for 1 h, and allow to cool in a desiccator.
. Ensure that the Benzyl Alcohol does not boil during evaporation. Dry the residue on the hot plate for 1 h, and allow to cool in a desiccator.
Acceptance criteria:
The residue weighs NMT 5 mg, corresponding to NMT 0.05%.
Organic Impurities
• Procedure: Benzaldehyde and Other Related Substances
Sample solution:
Use the Benzyl Alcohol sample under examination.
Standard solution A:
Dissolve 0.100 g of ethylbenzene in 10.0 mL of the Sample solution. Dilute 2.0 mL of this solution with the Sample solution to 20.0 mL.
Standard solution B:
Dissolve 2.000 g of dicyclohexyl in 10.0 mL of the Sample solution. Dilute 2.0 mL of this solution with the Sample solution to 20.0 mL.
Reference solution A (for use in nonparenteral applications):
Dissolve 0.750 g of benzaldehyde and 0.500 g of cyclohexylmethanol in the Sample solution, and dilute with the Sample solution to 25.0 mL. Add 1.0 mL of this solution to a mixture of 2.0 mL of Standard solution A and 3.0 mL of Standard solution B, and dilute with the Sample solution to 20.0 mL.
Reference solution B (for use in parenteral applications):
Dissolve 0.250 g of benzaldehyde and 0.500 g of cyclohexylmethanol in the Sample solution, and dilute with the Sample solution to 25.0 mL. Add 1.0 mL of this solution to a mixture of 2.0 mL of Standard solution A and 2.0 mL of Standard solution B, and dilute with the Sample solution to 20.0 mL.
Chromatographic system
Mode:
GC
Detector:
Flame ionization
Carrier:
Helium, chromatography grade
Carrier linear velocity:
25 cm/s, at 50
Detector temperature:
310
Column:
30-m × 0.32-mm, 0.5-µm film thickness, G16
Temperature
Column:
See the temperature program table below.
| Initial Temperature ( ) |
Temperature Ramp ( /min) |
Final Temperature ( ) |
Hold Time at Final Temperature (min) |
|---|---|---|---|
| 50 | 5 | 220 | 35 |
Injector:
200
System suitability
Sample:
For nonparenteral applications, use Reference solution A. For parenteral applications, use Reference solution B.
[Note—The retention time of benzyl alcohol is about 26 min. The relative retention times for ethylbenzene, dicyclohexyl, benzaldehyde, cyclohexylmethanol, and benzyl alcohol are about 0.28, 0.59, 0.68, 0.71, and 1.0, respectively. ]
Injection volume:
0.1 µL without air plug
Suitability requirements
Sensitivity:
Adjust the sensitivity of the detector so that the height of the peak due to ethylbenzene is NLT 30% of the full scale of the recorder.
Resolution:
NLT 3.0 between the peaks corresponding to benzaldehyde and cyclohexylmethanol
Analysis
Samples:
Sample solution and Reference solution A for non-parenteral applications and Reference solution B for parenteral applications
Acceptance criteria (non-parenteral applications):
If any peaks are present in the chromatogram obtained with the Sample solution that have the same retention times as the peaks due to ethyl benzene and dicyclohexyl, subtract the areas of any such peaks from the peak areas at these retention times in the chromatograms of Reference solution A or Reference solution B (corrected peak areas of ethylbenzene and dicyclohexyl). Any such peaks in the Sample solution should be included in the assessments for the total of other peaks.
In the chromatogram obtained with the Sample solution, the area of any peak corresponding to benzaldehyde is NMT the difference between the area of the peak due to benzaldehyde in the chromatogram obtained with Reference solution A (0.15%) and the area of the peak due to benzaldehyde in the chromatogram obtained with the Sample solution.
In the chromatogram obtained with the Sample solution, the area of any peak corresponding to cyclohexylmethanol is NMT the difference between the area of the peak due to cyclohexylmethanol in the chromatogram obtained with Reference solution A (0.10%) and the area of the peak due to cyclohexylmethanol in the chromatogram obtained with the Sample solution.
In the chromatogram obtained with the Sample solution, the sum of the areas of any peak with a relative retention time less than that of benzyl alcohol and apart from the peaks due to benzaldehyde and cyclohexylmethanol is NMT four times the area of ethylbenzene in Reference solution A, corrected if necessary as described above (0.04%).
In the chromatogram obtained with the Sample solution, the sum of the areas of any peak with a relative retention time greater than that of benzyl alcohol is NMT the area of dicyclohexyl in Reference solution A, corrected if necessary as described above (0.3%).
Disregard any peak with an area less than 0.01 times that of the peak due to ethylbenzene in the chromatogram of Reference solution A, corrected if necessary as described above.
Acceptance criteria (parenteral applications):
If any peaks are present in the chromatogram obtained with the Sample solution that have the same retention times as the peaks due to ethyl benzene and dicyclohexyl, subtract the areas of any such peaks from the peak areas at these retention times in the chromatograms of Reference solution A or Reference solution B (corrected peak areas of ethylbenzene and dicyclohexyl). Any such peaks in the Sample solution should be included in the assessments for the total of other peaks.
In the chromatogram obtained with the Sample solution, the area of any peak corresponding to benzaldehyde is NMT the difference between the area of the peak due to benzaldehyde in the chromatogram obtained with Reference solution B (0.05%) and the area of the peak due to benzaldehyde in the chromatogram obtained with the Sample solution.
In the chromatogram obtained with the Sample solution, the area of any peak corresponding to cyclohexylmethanol is NMT the difference between the area of the peak due to cyclohexylmethanol in the chromatogram obtained with Reference solution B (0.10%) and the area of the peak due to cyclohexylmethanol in the chromatogram obtained with the Sample solution.
In the chromatogram obtained with the Sample solution, the sum of the areas of any peak with a relative retention time less than that of benzyl alcohol and apart from the peaks due to benzaldehyde and cyclohexylmethanol is NMT two times the area of ethylbenzene in Reference solution B, corrected if necessary as described above (0.02%).
In the chromatogram obtained with the Sample solution, the sum of the areas of any peak with a relative retention time greater than that of benzyl alcohol is NMT the area of dicyclohexyl in Reference solution B, corrected if necessary as described above (0.2%).
Disregard any peak with an area less than 0.01 times that of the peak due to ethylbenzene in the chromatogram of Reference solution B, corrected if necessary as described above.
SPECIFIC TESTS
• Acidity
Phenolphthalein solution:
Prepare as directed in the Assay.
Analysis:
To 10 mL of Benzyl Alcohol add 10 mL of ethanol (96%) and 1 mL of Phenolphthalein solution.
Acceptance criteria:
NMT 1 mL of 0.1 M sodium hydroxide is required to change the color of the indicator to pink.
• Clarity of Solution
Clarity of Solution
[Note—The Sample solution is to be compared to Reference suspension 1 in diffused daylight 5 min after preparation of Reference suspension 1. ]
Hydrazine solution:
Transfer 1.0 g of hydrazine sulfate to a 100-mL volumetric flask, dissolve in and dilute with water to volume, and mix. Allow to stand 4–6 h before use.
Methenamine solution:
Transfer 2.5 g of methenamine to a 100-mL glass-stoppered flask, add 25.0 mL of water, insert the glass stopper, and mix to dissolve.
Primary opalescent suspension:
[Note—This suspension is stable for 2 months, provided it is stored in a glass container free from surface defects. The suspension must not adhere to the glass and must be well mixed before use. ] Transfer 25.0 mL of Hydrazine solution to the Methenamine solution in the 100-mL glass-stoppered flask. Mix, and allow to stand for 24 h.
Opalescence standard:
[Note—This suspension should not be used beyond 24 h after preparation. ] Transfer 15.0 mL of the Primary opalescent suspension to a 1000-mL volumetric flask, dilute with water to volume, and mix.
Reference suspension 1:
Transfer 5.0 mL of the Opalescence standard to a 100-mL volumetric flask, and dilute with water to volume.
Reference suspension 2:
Transfer 10.0 mL of the Opalescence standard to a second 100-mL volumetric flask, and dilute with water to volume.
Sample solution:
Dissolve 2.0 g of Benzyl Alcohol in 60 mL of water.
Analysis:
Transfer a sufficient portion of the Sample solution to a test tube of colorless, transparent, neutral glass with a flat base and an internal diameter of 15–25 mm, to obtain a depth of 40 mm. Similarly transfer portions of Reference suspension 1, Reference suspension 2, and water to separate matching test tubes. Compare the Sample solution, Reference suspension 1, Reference suspension 2, and water in diffused daylight, viewing vertically against a black background (see Spectrophotometry and Light-Scattering 851, Visual Comparison). [Note—The diffusion of light must be such that Reference suspension 1 can readily be distinguished from water, and that Reference suspension 2 can readily be distinguished from Reference suspension 1. ]
851, Visual Comparison). [Note—The diffusion of light must be such that Reference suspension 1 can readily be distinguished from water, and that Reference suspension 2 can readily be distinguished from Reference suspension 1. ]
Acceptance criteria:
The Sample solution shows the same clarity as that of water, or its opalescence is not more pronounced than that of Reference suspension 1.
• Color of Solution
Color of Solution
Sample solution:
Use the Sample solution prepared in the test for Clarity of Solution.
Analysis:
Transfer a sufficient portion of the Sample solution to a test tube of colorless, transparent, neutral glass with a flat base and an internal diameter of 15–25 mm, to obtain a depth of 40 mm. Similarly transfer a portion of water to a separate matching test tube. Compare the color of the Sample solution with that of water in diffused daylight, viewing vertically against a white background (see Spectrophotometry and Light-Scattering 851, Visual Comparison).
851, Visual Comparison).
Acceptance criteria:
The Sample solution has the color of water.
• Refractive Index 831:
1.538–1.541 at 20
831:
1.538–1.541 at 20
ADDITIONAL REQUIREMENTS
• Labeling:
Where Benzyl Alcohol is intended for use in the manufacture of parenteral applications, it is so labeled.
Labeling:
Where Benzyl Alcohol is intended for use in the manufacture of parenteral applications, it is so labeled.
• Packaging and Storage:
Preserve in tight containers, protected from light.
Packaging and Storage:
Preserve in tight containers, protected from light.
• USP Reference Standards
USP Reference Standards
USP Benzyl Alcohol RS 
') + '&img=../../images/v35300/cas-100-51-6.gif',600,500);)
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Robert H. Lafaver, M.S.
Scientific Liaison 1-301-816-8335 |
(EXC2010) Monographs - Excipients |
USP35–NF30 Page 1713
Pharmacopeial Forum: Volume No. 35(3) Page 685