Name: RAFAEL, DUNE VIENIS KAREN N. Year & Section: BS-Pharmacy 4ADate Performed: November 20, 2009 Rating: ____________________

Activity No. 04CHLOROFORM

Objectives:1. To detect the presence of chlorofrom by performing phenylisocyanide test, Schwartz’s test,

Lustgarten’s test, cyanide test and reduction tests namely, Fehling’s test and Tollen’s test,2. To understand the principles behind each test, and3. Interpret the results after performing each method of detection.

Data:Tests Observation/Results

1. Phenylisocyanide Test Actual: A foul odor was recognized.Ideal (+): A very penetrating and very repulsive odor is easily recognized (Warren, 1921).Blank (-): No odor was recognized.

2. Schwartz’s Resorcinol Test Actual: A yellowish-red color fluorescence was observed.Ideal (+): A yellowish-red color with a yellowish-green fluorescence is observed (Warren, 1921).Blank (-): A faint purple color was recognized.

3. Lustgarten’s Naphthol Test Actual: It changed from blue to green and finally turned to brown.Ideal (+): From an evanescent blue color, it changed to green and then to brown in contact with air (Warren,1921).Blank (-): No remarkable color change was noticed.

4. Reduction Testsa. Fehling’s Test Actual: There was formation of red precipitate.

Ideal (+): Red precipitate appears (Warren, 1921).Blank (-): No precipitates appeared.

b. Tollen’s Test Actual: Formation of silvery precipitate was observed.Ideal (+): A black precipitate of metallic silver appeared (Warren, 1921).Blank (-): No precipitation.

5. Cyanide Test Actual: There was formation of blue precipitateIdeal (+): Blue precipitation occurs (Warren, 1921).Blank (-): No precipitation can be observed.

Data Analysis

Phenylisocyanide TestThe penetrating and very repulsive odor of this compound is easily recognized. A.W. Hofmann

states that this test will show with certainty 1: 5,000 to 6,000 parts of alcohol. It should also be noted that chloral, chloral hydrate, bromoform, iodoform and tetrachloromethane also give this test (Warren, 1921).

CHC3 + C6H6NH2 + 3KOH C6H6NC + 3KCl + 3H2O

Schwartz’s Resorcinol TestThis mixture heated to boiling will develop even in very dilute solution a yellowish red color

attended by a beautiful yellowish green fluorescence. It should be noted that chloral, bromal bromoform and iodoform also give this test (Warren, 1921).

Lustgarten’s Naphthol TestChloroform will produce an evanescent blue color which in contact with air will change to green

and then to brown. This color is less stable when; 8-naphthol is used. Acidification of the blue solution will precipitate naphthol colored by a red dye stuff. This precipitate is usually brick-red. Chloral, bromal bromoform and idoform also give this test (Warren, 1921).

Cyanide TestA positive test means that the distillate contained chloroform and not because the solution is

contaminated with cyanide. The following reactions take place (Warren, 1921):(a) CHCI3 + H3N + 3KOH HCN + 3KCI + 3H2O

(Chloroform) (Ammonia) (Potassium hydroxide) (Hydrocyanic acid) (Potaasium chloride) (Water)

(b) HCN + KOH KCN + H2O(Hydrocyanic acid) (Potassium hydroxide) (Potassium cyanide) (Dihydrogen oxide)

(c) FeSO4 + 2KCN = Fe(CN)2 + K2SO4

(Ferrous sulfate) (Potassium cyanide) (Ferrous cyanide)

(d) Fe(CN)2 + 4KCN = K4Fe(CN)6

(Ferrous cyanide) (Potassium cyanide) (Potassium ferrocyanide)

(e) 3K4Fe(CN)6 + 4FeCl3 = Fe4[Fe(CN)6]3 ↓ + 12KCl(Potassium ferrocyanide) (Ferric chloride) (Ferric ferrocyanide/Prussian blue)

Reduction Tests: Fehling’s and Tollen’s TestThese reactions are not characteristic of chloroform, because many volatile organic substances,

as formic acid and aldehydes which may occur in distillates from animal material, reducs Fehling’s and Tollen’s reagents.

Answers to Questions:

1. What happens to chloroform when is enters the environment?

a. Air Given that the equilibrium partitioning of chloroform is over 99% into air,

atmospheric removal processes are the most important. Chloroform is oxidized by atmospheric hydroxyl radicals, present naturally at an average 9.5 x 10 -3 mol cm-3 (Prinn et al., 2001). The mechanism is typically (Euro Chlor, 2002):

(1) CHCl3 + OH → CCl∙ 3 +H∙ 2O(2) CCl3 + O2 CCl3OO ∙(3) CCl3OO + NO ∙ CCl3O + NO∙ 2

(4) CCl3OO + HO∙ 2 CCl3O + O∙ 2 + OH∙(5) CCl3O ∙ Cl CCl∙ 2O(6) CCl3O + RH ∙ CCl3OH + R∙(7) CCl3OH CCl2O + HCl

The first step (equation 1) is rate determining, with a rate constant of 8.1 x 10 -14 cm3 molecule-1 sec-1 at 277 oK, so that the atmospheric lifetime of chloroform is 0.5 years [Prather, 1995]. Based on the concentrations reported in Khalil and Rasmussen [1999], the removal rates of chloroform by atmospheric oxidation are in the region of 410 Gg yr-1 in the northern hemisphere and 190 Gg yr-1 in the southern. Particularly in view of the vertical concentration profile, but also because of uncertainties in the reaction rate constant and the measurements themselves, these mass destruction rates have wide ranges: from 570 to 250 Gg yr-1 (NH) and 260 to 120 Gg yr-1 (SH). These calculations were performed using the simple two-box hemispherical model described in McCulloch and Midgley [1996] and so are illustrative, rather than substantive. Nevertheless, the global total is in good agreement with the emissions that were calculated directly in section 2 above, even if the distributions reflect a bias in the latter towards the northern hemisphere (Euro Chlor, 2002).

b. Soil and SedimentSeveral methanogens have been shown in the laboratory to dechlorinate

chloroform, particularly when promoted by metallic iron (Fe0) [Novak et al., 1998a; 1998b]. While this has little importance in the global mass balance of chloroform, it may be significant for groundwater; based on the kinetic data given for carbon tetrachloride degradation by the same organisms, the half-life for chloroform is about 12 hours. Although the product(s) were not identified, the mechanism of the process, driven by an unidentified enzyme, suggests methane.

Chloroform is also degraded aerobically by Methylosinus trichosporium. In this case, the responsible enzyme is methane monooxygenase and the loss of chlorine follows insertion of oxygen into the C-H bond. The product is carbon dioxide [Bartniki and Castro, 1994].

c. WaterAlthough chloroform hydrolyses readily in alkaline conditions [Hine and Dowell,

1954], the dependence of the rate on hydroxyl ion concentration means that, under the conditions prevailing in environmental water, its half-life is greater than 1,000 years and hydrolysis is not an effective sink.

2. Is chloroform likely to cause cancer?The US Environmental Protection Agency concluded that chloroform is not likely to be

carcinogenic to humans by any routes of exposure at a dose level that does not cause cytotoxicity and cell regeneration. This conclusion is supported by the finding that chloroform is not a strong mutagen and is not likely to cause cancer through a genotoxic mode of action. Hence daily exposure to 10,000 ng kg-1 body weight (600,000 ng day-1 for an adult person) is safe from the point of view of carcinogenicity [USEPA, 2001]. Based on a daily consumption of 1.5 kg food and 2 litres of water based beverages per person, the chloroform levels in drinking

water (13 µgL-1 [Krasner, et al., 1989]) and foodstuff (52-71 µg.kg-1 [Crookes et al. [1994]) are of no concern.

Conclusion:Inhaled chloroform first passes from the air into the blood-plasma which then transmits it to the

red blood corpuscles where it may accumulate in relatively large quantity. Air passed through blood will remove chloroform completely. Absorption of chloroform is rapid from all parts of the body. The stimulative action of chloroform on the mucous membranes of the respiratory passages explains such disturbances as coughing, secretion of saliva and reflex slowing of respiration and heart-beat, occurring at the beginning of narcosis. Dilatation of the blood-vessels of organs living after death is due to paralysis caused by even small doses of chloroform. A drop in blood pressure accompanies paralysis of the brain and the heart’s action is feebler and slower. With this in mind, pharmacists play a vital role in the management in cases of chloroform intoxication. With this activity, I understood and acquired skills on the detection of chloroform in the laboratory aside from management using pharmaceutical means. Chloroform is detected in the laboratory by performing the phenylisocyanide test, Schwartz’s test, Lustgarten’s test, cyanide test and reduction tests namely, Fehling’s test and Tollen’s test.

Bibliography

Euro Chlor. (2002). Chloroform in the Environment Occurence, Sources, Sinks and Effects. Brussels: Euro Chlor.

Warren, W. H. (1921). Laboratory Manual for the Detection of Poisons and Powerful Drugs. New Jersey: Read Books.