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Boiling point

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Reference
Endpoint:
boiling point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
before 12 Apr 2006
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Qualifier:
no guideline followed
Principles of method if other than guideline:
simple distillation and alternate method (reducing the heat history and blanketing the substance with nitrogen)
GLP compliance:
no
Type of method:
distillation method
Boiling pt.:
>= 259 - <= 260 °C
Atm. press.:
ca. 1 013 hPa
Decomposition:
yes

The determination of the AEPD's boiling point by simple distillation:

Fraction No.

Temp. range, °C

Weight obtained, g

Comment

GC Analysis (% AEPD)

1

RT-250

0.5

2 phases

8.5

2

250-259

1.0

yellow oil

80

3

259-260

2.0

yellow oil

94

4

>260

0.5

yellow oil

98.9

The majority of the substance distilled overhead in Fraction 3 (259-260 °C) even though some decomposition occurred at these elevated temperatures while open to the atmosphere. The purity dropped to 94.4 area% in the main fraction collected. Thus it appeared possible that this measured bp was lower than the actual value.

The results of the boiling point determination of AEPD at atmospheric pressure:

Measure No.

Method used

Boiling point, °C

Device used

AEPD purity, area%

1

Distillation (method 1)

259-260

Thermometer #1

94.4

2

Boiling point (method 2)

259.0

Thermometer #2

99.8

3

Boiling point (method 2)

260.0

Thermometer #3

~99

4

Boiling point (method 2)

253.5

Thermometer #4

~97

5

Boiling point (method 2)

262.2

J Thermocouple

~96

6

Boiling point (method 2)

256.5

Thermometer #5

~95

7

Boiling point (method 2)

258.0

Thermometer #3

93.2

Heating the substance to its boiling point at atmospheric pressure had caused decomposition to occur. While this was most apparent when performing the simple distillation using a short path distillation system to take the AEPD overhead, the alternate method also resulted in decomposition even thought it was run under nitrogen and had a shorter heat history. Obviously this decomposition affects the reported bp as measurement #3 and #7 used the same thermometer / set-up; yet the bp for measurement #3 (99.5 area%) was 2.0 °C more than measurement #7 (93.2 area%) that had been heated for about an hour under nitrogen. Therefore adding 2.0 °C to run #7 and then throwing the low and the high bp values out, a value of 259 °C is reached as the boiling point of the AEPD. This matches the simple distillation value previously obtained.

Conclusions:
The AEPD (2-amino-2-ethyl-1,3-propanediol) standard was prepared and then characterized by GC, GC/MS (EI and CI), NMR (1H and 13C), IR and titration determination that confirmed the assigned structure. This high purity material (99.5+%) was subsequently used to determine its boiling point as 259-260 °C at atmospheric pressure by two different methods.

Description of key information

259-260 °C at ambient pressure

Key value for chemical safety assessment

Boiling point at 101 325 Pa:
259 °C

Additional information

Distillation method. Decomposition occurs. Under reduced pressure of 10 mmHg, 152 -153 °C reported (handbook data).