Shell Method Series
SMS 1968-09
-------------------------------------------------------------------------------------------------------------------------------------- © Shell Global Solutions International B.V. 2009.
Page 1 (9 pages)
Determination of
ACIDITY AND CARBON DIOXIDE CONTENT
OF ETHYLENE OXIDE
Colour Indicator Titration Method
SAFETY
This SMS method (“this method”) may involve hazardous materials, operations and/or equipment. This method may not completely address all safety problems associated with its use. It is the responsibility of the user of this method to establish appropriate health, safety and environmental practices, and to determine the applicability of local laws and regulations, prior to its use.
LIABILITY
The user of this method accepts that, to the fullest extent permitted by law, Shell Global Solutions International B.V. (“SGSI”) and its affiliated companies do not give any representations or warranties in relation to this method or use of this method and shall not be liable for any damage to property or injury to persons, or for any loss of income or profit, loss of use or production or other indirect or consequential damage, resulting from use of this method.
INTELLECTUAL PROPERTY RIGHTS
All and any intellectual property rights in this method belong to SGSI and/or its licensors. Neither the whole nor any part of this method may be reproduced or copied in any form, provided to a third party or used for any purpose which has not been expressly agreed with SGSI without (in each case) the prior written consent of SGSI.
1. SCOPE
This method describes the determination of acidity (expressed as acetic acid) and carbon dioxide content, down to levels of 2 mg/kg and 4 mg/kg, respectively, of ethylene oxide (1,2-epoxyethane).
2. WARNING
Ethylene oxide and its solutions are extremely flammable and is toxic by inhalation. Irritating to eyes, respiratory system and skin. Risk of explosion if heated under confinement. May cause cancer. May cause heritable genetic damage. Keep away from sources of ignition. Keep container in a well ventilated, cool place. Handle only under a well-ventilated hood and use suitable gloves.
Knowledge of the acidity and carbon dioxide content of ethylene oxide are required for process quality control during subsequent manufacturing processes.
SMS 1968 - 09
4. DOCUMENTS
4.1. Methods
ASTM D1265 "Practice for Sampling Liquefied Petroleum (LP) Gases, Manual Method"u87
ASTM D1193 "Specification for Reagent Water"
SMS 1000"Accuracy (Precision and Trueness) of SMS Methods"
SMS 1004 "Determination of Capacity of Volumetric Glassware"
SMS 1006 "Statistical Control of Test Methods"美国丽人下载
SMS 1014 "Calibration and Verification of (Analytical) Balances".
4.2. Other
Material Safety Data Sheets (MSDS), for the chemicals described in this method. For Shell products, refer to www.shell/chemicals, for other products these are available the reagent supplier.
The manufacturer’s instruction manual(s) of the equipment as described in Section 6.
5. METHOD SUMMARY
Two portions of ethanol are cooled to a maximum temperature of 10 °C. The first portion is neutralized, an amount of test sample is added and the solution is boiled to expel carbon dioxide.
The remaining solution is titrated with standard potassium hydroxide solution. The second portion is neutralized, an amount of test sample is added and the homogenized solution is titrated cold with standard potassium hydroxide solution. The acidity of the sample is calculated from the data obtained from the first titration whilst the carbon dioxide content of the sample is determined from the difference between the two titration volumes.
6. APPARATUS
6.1. Sample Container, suitable for ethylene oxide and its concentrated aqueous solutions: a
stainless steel cylinder, maximum capacity 500 mL, with an enviroflow valve which provides a closed sampling system and prevents the cylinder from overfilling with ethylene oxide through a pre-sized dip tube.
日本人眼里的中国
Note 1. The Enviro flow bomb system, manufactured by Expotech USA Inc.,
Houston, TX 77099, USA, has been found suitable.
Page 2
SMS 1968 - 09
6.2. Cooling Device: either an ice-bath, or a refrigerator at maximum temperature of 10 °C.
6.3. Heating Device: either a steam bath or a heating plate, sparkless, e.g. using an oil bath, 50
°C.
6.4. Evaporation Hood, glass, suitable to enclose one or more beakers (6.9), height approx.
130 mm, diameter 250 mm, with a nitrogen inlet having its end drawn out to a jet, and with outlet.
See Fig.1. (only if a heating plate is used).
6.5. Gas Flowmeter, e.g. of the rotameter type, capable of measuring a nitrogen flow rate of
between 175 and 200 L/h. (only if a heating plate is used).
6.6. Oven, temperature 120 ± 5 °C.
6.7. Analytical Balance, readability 0.1 mg, calibrated. It is recommended to calibrate or verify at
国家意志regular intervals, e.g. as described in SMS 1014. 6.8. Desiccator, with dried silica gel.
6.9. Glassware
•(automatic) burette: 25 mL,
•brown-glass bottles: 1 L,
•conical flasks or beakers: 250 mL,
•volumetric flask: 1 L,
•graduated cylinders: 50 mL.
In cases where volumetric glassware is to be used, it shall conform to Grade (or Class) A specificatio
ns as described in, e.g. ISO 1042 or ASTM E 288 for volumetric flasks, or ISO 648 or ASTM E 969 for one-mark pipettes. For optimum accuracy, it is recommended to calibrate volumetric glassware at regular intervals, e.g. as described in SMS 1004.
7. REAGENTS AND MATERIALS
7.1. The following reagents and materials are required as such or for preparation of solutions
applied:
7.1.1. Ethanol, carbon dioxide free. Protect against carbon dioxide absorption by stripping
with nitrogen and store under nitrogen.
Note 2. CAUTION. Highly flammable. Keep container tightly closed. Keep away
from sources of ignition.
7.1.2. Nitrogen, dry and free of extraneous matter.
7.1.3. Phenolphthalein Indicator.
Page 3
SMS 1968 - 09
Page 47.1.4. Potassium Hydrogen Phthalate, A.R. Dry in an oven at 120 ± 5 °C for 2 hours. Stopper the container and store in a desiccator.
7.1.5. Potassium Hydroxide, A.R (only required if no ampoules are used for preparation of potassium hydroxide solution; 7.2.1).
Note 3. CAUTION. Causes severe burns. In case of contact with eyes, rinse
immediately with plenty of water and seek medical advice. Wear suitable gloves
and eye/face protection. In case of accident or if you feel unwell, seek medical
advice immediately.
7.1.6. Water. For all purposes where water is mentioned, use reagent water, e.g. type II as described in ASTM D 1193, or better. Protect from atmospheric absorption of carbon dioxide during storage by means of a guard tube filled with a suitable carbon dioxide absorbent.
Note 4. A suitable carbon dioxide absorbent is "Carbosorb AS", available from
BDH Laboratory Supplies, Poole, Dorset BH15 1TD, United Kingdom.
7.2. Solutions:
7.2.1. Potassium Hydroxide Solution, standard, c(KOH) = 0.01 mol/L. Either use
ampoules containing concentrated solutions for preparation of standard volumetric solutions and prepare according to the manufacturer's instructions (see Note 6), or prepare as follows: Prepare a 0.1 mol/L solution by dissolving 6.5 g of A.R. potassium hydroxide (CAUTION.
See Note 3) in carbon dioxide-free water, dilute to 1 L and mix thoroughly. Decant the solution into a brown-glass storage bottle. To protect against carbon dioxide absorption provide the storage bottle with a guard tube filled with carbon dioxide absorbent (see Note
4). Standardize as described in Section 8.
To obtain the concentration (c1) of the standard 0.01 mol/L solution, accurately dilute the standard 0.1 mol/L solution to a ten-fold volume with carbon dioxide-free water. Strip with nitrogen and store under nitrogen in a brown-glass bottle.
Note 5. A.R. potassium hydroxide normally contains 85 to 90 %(m/m) KOH.
Note 6. Ampoules containing concentrated solutions for preparation of standard
volumetric solutions are available from various suppliers, e.g. Titrisol® from Merck
KGaA, Frankfurterstraße 250, D-64293 Darmstadt, Germany.
7.2.2. Phenolphthalein Indicator Solution, 1 %(m/m) in 60 %(V/V) ethanol in carbon
dioxide-free water.
7.3. Quality Control Sample: It is recommended to select a sample, similar or equivalent to the product being analyzed (CAUTION. See Section 2) having a known (and typical) acidity and/or concentration of carbon dioxide, and to use it as a quality control sample. To this end, ensure to store the sample in such a way that it is stable for a known period of time and use it as such during this period of time only. For more details, see 10.6.
SMS 1968 - 09
Page 5 8. STANDARDIZATION
Standardize the 0.1 mol/L potassium hydroxide solution in triplicate as described below. Repeat standardization at least once a week to detect changes in the concentration as small as 0.0005 mol/L.
8.1. Weigh 0.95 ± 0.05 g of dried potassium hydrogen phthalate (7.1.4) to the nearest 0.1 mg into a 250 mL conical flask. Add 100 mL of carbon dioxide-free water, swirl gently to dissolve and add three drops of phenolphthalein indicator solution. Titrate to the faint pink end-point with the 0.1 mol/L potassium hydroxide solution.
8.2. Calculate the concentration of the potassium hydroxide solution, for each of the three titrations, to the nearest 0.00001 mol/L, by means of the following equation:
31110204.23
V m = mol/L ,ion Concentrat ××
where:
m 1 = mass of potassium hydrogen phthalate taken (8.1), g,
V 1 = volume of potassium hydroxide solution consumed to the end-point (8.1), mL,
and 204.23 is the relative molecular mass of potassium hydrogen phthalate.
If the difference between the lowest and the highest of the three values obtained is greater than 0.50% relative to the mean, repeat the Standardization. If not, calculate the concentration (c) of the standard 0.1 mol/L potassium hydroxide solution by averaging the three values, rounding off to the nearest 0.0001 mol/L.
9. SAMPLING
9.1. For sampling of ethylene oxide and concentrated aqueous solutions thereof, follow the instructions as described in ASTM D1265 for liquefied (petroleum) gases, using a suitable sample container (6.1) and filling it to a maximum of 70% of its capacity (CAUTION . See Section 2).
约翰萨顿9.2. For analysis, place the cylinder in a vertical position on a grounded rack or on the enviroflow male adapter in the hood for sample withdrawal. If the analysis is not performed immediately, the sample cylinder can be placed in a refrigerator to keep pressure down. However, lengthy storage should be avoided.
豫公网安备41160202000603
站长QQ:729038198
关于我们
投诉建议