Trichloroethylene三氯乙烯.pdf

488/Trichloroethylene/ Monograph
REQUIREMENTS
dichloroethylene
Identification
Ethylene Trichloride; Trichloroethene; 1, 1, 2
A. Heat a few drops of sample in a test tube with about Trichloroethylene
500 mg of polassium bisulfate. Pungent vapors of acrolein
evolve
C
B. The solution resulting from the Assay(below )gives
Positive tests for Acetale, Appendix IIA
ly Not less than 98.5% of C9H14O
Lead Not more than 1 mo/k
C,HC
Formula wl 13139
Refractive Index Between 1.429 and 1 431 at 25
CAS:[79-01-6
Specific Gravity Between 1.154 and 1.158
Unsaturated Compounds Passes lest
Water Not more than 0.2%
DESCRIPTION
TESTS
Trichloroethylene occurs as a clear, colorless liquid free from
sediment and suspended matter. It is immiscible with water
Assay Transfer about 1 g of sample, accurately weighed, but is miscible with alcohol, with ether, and with acetone. Its
into a suitable pressure bottle; add 25.0 ML of I N polassium
refractive index al 20 is aboul 1 477. lt may contain a suitable
hydroxide and 15 ML of isopropanol; stopper the bottle, and stabilizer
wrap securely in a canvas bag. Place in a water bath maintained
and heat for I h, allowing the water in the bath Function Extraction solvent
to just cover the liquid in the bottle. Remove the bottle from
the bath, cool in air to room temperature, then loosen the
wrapper, uncap the bottle to release any pressure, and remove
REQUIREMENTS
the wrapper. Add 6 to 8 drops of phenolphthalein TS, and
Identification Transfer 5 ML of sample into a glass-stop
titrate the excess alkali with 0.5 N sulfuric acid just to the
pered lest tube, add 5 ml of bromine TS, and shake vigorously
disappearance of the pink color. Perform a blank determina-
every 15 min for I h. The color of the bromine fades. and a
Lion(see General Provisions), and make any necessary correc- white turbidity forms in the lower layer
tion. Each milliliter of 0.5 N sulfuric acid is equivalent to
Acidity (as HCI)Not more than 10 mg/kg
36.37 mg of COHI4O6
Alkalinity (as NAOH)Not more than 10 mg/kg
Acidity Transfer about 25 g of sample, accurately weighe
Distilation Range Between86°and88°
into a 125-ml conical flask; add 50 ml of toluene and 2 Free Halogens Passes test
drops of thymol blue TS: and titrate rapidly with 0.02 M Lead Not more than 1 mglkg
sodium methoxide in toluene. Swirl the nask continuously
Nonvolatile Residue Not more than 10 m/k
until the yellow color changes to a dark color, and then con-specific Gravity Between 1454 and 1.458
tinue the titration without stopping bul slowing the addition water Not more than 0.05%
of titrant until a single drop changes the solution to a clear
blue color. The endpoint is stable for about 8 to 15 S. Not
more than 1.0 ml of 0.02 M sodium methoxide is required
TESTS
Lead Determine as directed or Method I in the fomic Acidity(as Hcl)or Alkalinity(as NAOH) Transfer 25 ml
dbsorplion Spectrophometric Graphile Furnace de hod un- of water and 2 drops of phenolphthalein TS into a 250-ml
der Lead Limit Test, Appendix IIIB
glass-stoppered flask, and add 0.01 N sodium hydroxide to
Refractive Index Determine as directed under Refraetive the first appearance of a slight pink color. Add 25 ml of
Index, App