Applications MP Systems Rudolf Riesen April 2009 Author: R. Riesen Date: April 09; V1.1 Approved: M. Wagner
Applications MP Systems
Rudolf RiesenApril 2009
Author: R. RiesenDate: April 09; V1.1Approved: M. Wagner
Internal usage only
Agenda
� Melting point determination; statistics, precision
� Identification by mixed melting point
� Melting and decomposition
� Melting point of inorganic substances
� Liquid crystals
� Phase transition with color changes
� Identification of rubber chemicals (ASTM D1519)
� Melting of polymers
� Overview of standards
� Summary
1
Melting events
JIS K 0064 – 1992
Test methods for melting point and melting range of chemical products
2
Melting events
Measurement of the light transmission� A: Start of melting
� B: Melting point (intensity 40%)
� C: End of melting
� Pharmacopeia: furnace temperature
� Thermodynamic: corrections by thermal lag:
fA = 0.2 KfB = 1.5 KfC = 2.0 K
ββ fTT −= )(phth
3
Analysis of the melting of benzoic acid (I)
Data: 15 sets of 6 benzoic acid test specimens measured in the MP. Heating rate 1 K/min; thermodynamic melting temperature
1 2 3 4 5 6122.2
122.3
122.4
122.5
122.6
122.7
122.8
122.9
123.015 measurements
Mel
ting
tem
pera
ture
in °C
Position4
Dependency of the melting point on the filled heigh t(25 mm in the video = 4 mm in the capillary)
Analysis of the melting of benzoic acid (II)
122.3 122.4 122.5 122.6 122.7 122.8 122.920
22
24
26
28
30 ρ = 0.49
Fill
hei
ght i
n m
m
Melting temperature in °C5
Distribution of the melting point : Gaussian (χ2 = 1.5; χ2krit = 7.8)
Analysis of the melting of benzoic acid (III)
122.2 122.4 122.6 122.8 123.00
5
10
15
20
25
Fre
quen
cy
Melting Temperature in °C
Measured
Gaussian µ = 122.56 °C σ = 0.133 °C
6
Analysis of the melting of benzoic acid (IV)
Comparison MP – FP results (Certified material: 122.3 ±0.2 °C)
F-test for the standard deviations of the MP and the FP results: the 2 standard deviations are compliant to each other; i.e. the precision of the 2 instruments regarding the melting point of benzoic acid is the same.
Remark: the results show, that the 95% confidence interval is well below the specified precision of the reference material. This raises questions:
- are our instruments so outstanding?
- is the reference material so poorly specified?
- what is precision?
7
MP FP n 85 21 Mean 122.56 °C 122.51 Standard deviation 0.13 °C 0.10 °C
Confidence interval (95 %) (based on 6 capillaries)
0.09 °C
0.07 °C
Remarks to the notion of “Precision” (I)
Precision can be defined on different levels
System Precision
Repeatabilitydifferent sample preparation
Intermediate Precisiondifferent operator, instrument, time
Reproducibilitydifferent labs, time (long term)
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Remarks to the notion of “Precision” (II)
� System precision: the same test specimen is measured under identical conditions
� Repeatability: the same operator prepares and measures several test specimens under otherwise identical conditions
� Intermediate precision: several operators prepare and measure several test specimens on different instruments with the same methods
� Reproducibility: the same sample is measured under intermediate precision conditions in several laboratories.
� The precision indicated on reference materials should correspond to a reproducibility precision
� The precision indicated here for benzoic acid measurements corresponds to a repeatability precision
9
Internal usage only
Agenda
� Melting point determination, statistics, precision
� Identification by mixed melting point
� Melting of critical substances, decomposition
� Melting point of inorganic substances
� Liquid crystals
� Phase transition with color changes
� Identification of rubber chemicals (ASTM D1519)
� Melting of polymers
� Overview of standards
� Summary
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Identification by mixed melting point
� Two samples of urea have to be compared.
� The measurements shall show if both samples are of the same chemical.
� Procedure:Determination of the melting points of the individual substances and the melting point of the 1:1 mixture.
� Equipment: MP90 is used.
� Sampling:6 capillaries were filled for each measurement (totally 36).
� Method:Melting range according to pharmacopeia (1 K/min, furnace temperature).
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Identification by mixed melting point
� Lit. Value: 132 - 135 °C (Ph.EUP. 2.2.14)
� Decomposing
12
Identification by mixed melting point
Results
Same chemicals; Urea 2 is a little less pure
13
131
132
133
134
135
136
Urea 2Urea 1
Tem
pera
ture
in °C
Mixture
Melting and decomposition
� Sample: Sugar
� Method: - Operation mode: Melting point- Criterion: Threshold 10%- Start temp.: 180 °C- Rate: 1 °C/min- End temp.: 190 °C- Temp. Values: Pharmacopeia
� Results: - Mean value: 187.3 °C- Std. dev.: 0.1 °C
Decomposition
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Critical results:
� Melting point is scattered
� Transmission curves are not regular
� Samples get brownish
� Check the video for bubbles
New definition: blow point
Melting and decomposition
15
Internal usage only
Agenda
� Melting point determination, statistics, precision
� Identification by mixed melting point
� Melting of critical substances, decomposition
� Melting point of inorganic substances
� Liquid crystals
� Phase transition with color changes
� Identification of rubber chemicals (ASTM D1519)
� Melting of polymers
� Overview of standards
� Summary
10
Inorganic substances
� Sample: Potassium nitrate (KNO3)
� Method: - Operation mode: Melting point- Criterion: Threshold 40%- Start temp.: 328 °C- Rate: 1 °C/min- End temp.: 339 °C- Temp. Values: Thermodynamic
� Results:- Mean value: 334.67 °C- Std. dev.: 0.18 °C
Melting Point
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Liquid crystal
Azoxydianisol: nematic – isotropic transition
Start of transition: 133.12 °C ±1.42 °CEnd of transition: 134.27 °C ±0.02 °C
Melting of crystals LC Transition
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Liquid crystal
Transmission light
19
Liquid crystal
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Thermo chromic substance
Thermo chromism
Transition with color change
� Sample: HgI2� Method:
- Operation mode: Set manually
- Start temp.: 120 °C
- Rate: 5 °C/min- End temp.: 155 °C
- Temp. Values: Pharmacopeia
� Results:- Point 1: 142.25 °C- Point 2: 155.00 °C
21
Thermo chromic substance
Phase transition with color change:
137 °C 145 °C
148 °C 155 °C22
Color changes by loss of water
CuSO4·5H2O CuSO4·3H2O CuSO4·1H2O CuSO4
60 °C 110 °C
150 °C 280 °C23
Internal usage only
Agenda
� Melting point determination, statistics, precision
� Identification by mixed melting point
� Melting of critical substances, decomposition
� Melting point of inorganic substances
� Liquid crystals
� Phase transition with color changes
� Identification of rubber chemicals (ASTM D1519)
� Melting of polymers
� Overview of standards
� Summary
10
ASTM D1519, rubber chemicals
ASTM D1519 - 95(2004)e1 Standard Test Method for Rub ber Chemicals - Melting Range
1. Scope1.1 These test methods cover the determination of the melting range of commercial rubber processing chemicals either by use ofcapillary melting point tubes or by differential scanning calorimetry (DSC).
6. Apparatus6.1 Melting Apparatus—Any electric melting apparatus that satisfies the requirements of Test Method E 324 may be used or any suitable manually heated oil bath such as Hershberg tube.
E324 (withdrawn) :1. Scope1.1 This test method covers the determination, by a capillary tube method, of the initial melting point and the final melting point, which define the melting range, of samples of organic chemicals whose melting points without decomposition fall between 30 and 250°C.
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ASTM D1519, rubber chemicals
� Tested substances (listed in ASTM D1519-82)- TETD (Tetraethylthiuramidsulfid): 69 – 70 °C
- PBNA (Phenyl-beta-naphtylamin): 104 -107 °C- MBT (Marcaptobenzothiazol): 175 – 180 °C
� Industrial applications:- TETD: accelerator for vulcanization reactions
- PBNA: antioxidant for rubbers- MBT: accelerator and antioxidant in rubbers
� Experimental:- Melting range (pharmacopeia)
- Tstart = Texpected – 10 K
- Rate: 1 K/min- Double determination
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ASTM D1519, rubber chemicals
Melting ILT FP81HT MP90TEDT Tstart x in °C 69.00 70.00 70.60
s in °C 0.03 0.11 0.03Tend x in °C 70.80 70.50 71.60
s in °C 0.21 0.07 0.18PBNA Tstart x in °C 103.80 107.50 107.30
s in °C 0.28 0.78 0.07Tend x in °C 107.40 §1 108.40
s in °C 0.23 0.20MBT Tstart x in °C 174.80 178.30 177.20
s in °C 0.49 0.39 0.13Tend x in °C 179.60 §1 181.10
s in °C 0.43 0.24
x mean of 12 specimens standard deviation
§1 transmission below 20%
ILT: inter-laboratory round robin test in 1982
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Polymers
Polymers
� Sample: Lupolen 1800H & 6031HLDPE, HDPE
� Method: - Operation mode: Melting point
- Start temp.: 95/125 °C
- Rate: 5 °C/min- End temp.: 125/145 °C
- Temp. Values: Thermodynamic
� Results:- LDPE: 103.49 °C- HDPE: 132.40 °C ISO 3146 (Plastics – Determination of melting
behavior of semi-crystalline polymers)
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Overview of standards
Ph.Eur. 2.2.60 (Melting point – Instrumental method)
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Overview of standards
Complying (metal block, automatic detection)� Mentioned in brochure
- Ph.Eur. 2.2.60 (Melting point – Instrumental method)- USP <741> (Melting range or temperature)- JIS K 0064 (Melting point and melting range of chemical products)- ASTM D1519 (Rubber Chemicals – Determination of Melting Range)
� Additional- ISO 3146 (Plastics – Determination of melting behavior of semi-crystalline
polymers)
Close standards (for example oil bath with thermome ter)
� Japanese Pharmacopeia
� AOCS Cc 1-25 (Melting Point, Capillary Tube Method)
Manual standards should be replaced by MP90 procedu re
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Summary
Application MP50 MP70 MP90 Melting point • • • Melting range • • • Purity determination • • • Decomposition temperature � • • Solvent loss � • • Sublimation � • • Change in the crystal structure � • • Sintering point � • • Color change • • Thermochromism • • High throughput analysis •
• Suitable � partly suitable31
Acknowledgment
The measurements have been performed by my colleagues:� Claudia Frisch� Angela Hammer� Ni Jing� Myrta Pfister � Nicolas Fedelich� Kai Hassdenteufel� Thomas Oberholzer � Jürgen Schawe � Markus Schubnell� Matthias Wagner
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Discussion
Questions
Answers
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Excellence Melting Point Systems
April 2009