Analysis of Water-Soluble Chlorohydrins and Other Organic Chlorides

LELLA TRAFELET, Wyandotte Chemicals Corporation, Wyandotte, Mich.

A method of quantitatively determining chlorohydrins in mixtures with other organic chlorides and inorganic chlorides is presented. The chlorides are selec- t ively hydrolj zed with alkalies and the resulting alkali chloride is volumetrically determined bj titrating with silver nitrate by the Mohr method (2).

HE method described below provides means of differentiat- T ing the chlorine combined in the chlorohydrins from the chlorine in such other compounds as inorganic chlorides, organic dichlorides, and dichloro ethers. A4 survey of the literature revealed t r o methods of replacing

the chlorine of aliphatic chlorohydrins with the OH group. Francis ( I ) states that chlorohydrins are quantitatively converted to glycols by heating with a solution of sodium bicarbonate. Uhrig (3) used hydrolysis with sodium hydroxide to determine chlorohydrins.

Experimental work using sodium bicarbonate as hydrolyzing agent showed that chlorohydrins were selectively hydrolyzed with this agent to the glycol and sodium chloride. Other ali- phatic chlorides were unaffected. On the other hand, sodium hy- droxide not only hydrolyzed the chlorohydrins to glycols and sodium chloride but also hydrolyzed the small amounts of other aliphatic chlorides which were dissolved in the chlorohydrins.

I t is possible by these means to determine the inorganic chlo- ride present in the sample, and then by using two hydrolyses to determine the chlorohydrin chloride and the other aliphatic chlorides such as ethylene dichloride, propylene dichloride, and the respective dichloro ethers.

REAGENTS

0.1 S silver nitrate, standardized; dilute sodium hydroxide, 4%; dilute sulfuric acid, 5YG; 5 ' 5 aqueous sodium chromate; C.P. solid sodium bicarbonate; and phenolphthalein indicator.

APPARATUS

Gas or electric hot plate; condenser rack. Reflux water-cooled condensers with standard-taper ground-glass joints, approxi- mately 16-inch (40-cm.) jacket; 250-ml. flasks with standard- taper ground-glass joints to fit condensers; 250-ml. wide-mouthed Erlenmeyer flasks: 50-ml. burets; 100-ml. volumetric flask; and 10-ml. pipet.

PROCEDURE

Accurately weigh to * 1 mg. a sample of such size that when it is diluted to 100 ml., 5 ml. will contain approximately 0.25 gram of chlorohydrin. Transfer t o a 100-ml. volumetric flask and make up to the mark with distilled water. Use aliquots for the following tests.

Inorganic Chloride. Pipet a 5-ml. aliquot into a 250-ml. Erlenmeyer flask containing approximately 50 ml. of distilled mater, and add several drops of phenolphthalein indicator. If pink, neutralize the contents of the flask with dilute sulfuric acid until the pink color is just destroyed; if colorless, add dilute sodium hydroxide until faintly pink, then destroy pink color with 1 or 2 drops of dilute sulfuric acid. Add 1 ml. of the 57c sodium chromate and titrate the mixture with 0.1 N silver nitrate until the first permanent appearancte of the red precipitate of silver chromate. Each milliliter of 0.1 -V silver nitrate is equivalent to 0.003546 gram of chlorine.

111. of 0.1 S silver nitrate X 0.3546 X 20 = chlorine rv 68

when TV = weight of sample which was diluted to 100 ml. Record per cent chlorine as A .

Pipet a 5-ml. aliquot into a 250-ml. Erlenmeyer flask with 24/40 standard-taper ground-glass joint, add approximately 50 ml. of water and 2 grams of C.P. sodium bi- carbonate, attach to reflux condenser, and reflux a t boiling for 30 minutes. Remove the flask from the hot plate and cool the con- tents to room temperature. Add several drops of phenol- phthalein indicator, neutralize the contents of the flask, and ti- trate with 0.1 S silver nitrate as described above for inorganic chloride. Calculate and record per cent chlorine as B.

B - A = 7G C1 combined in chlorohydrin

Organic Chlorides. Pipet a 5-ml. aliquot into a 250-ml. Erlenmeyer flask with 24 140 standard-taper ground-glass joint, add approximately 50 ml. of distilled water and 10 ml. of dilute sodium hydroxide, attach t o the reflux condenser, and reflux for 1 hour. Remove the flask from the hot plate, cool to room tem- perature, neutralize to phenolphthalein, and titrate as described above for inorganic chloride. Calculate and record per cent chlorine as C.

C - B - A = yo C1 present in organic materials other than chlorohydrins.

Chlorohydrin Chloride.

RESULTS AND DISCUSSION

Aqueous mixtures of inorganic chloride, ethylene chlorohydrin, propylene chlorohydrin, dichloroethyl et her, dichloroisopropyl ether, ethylene dichloride, and propylene dichloride were made which contained these components in varying amounts. Table I gives the exact composition of the mixtures and lists the analyti- cal results obtained in the laboratory and the theoretical values calculated from per cent chlorine in the various compounds.

This method has been found applicable for analysis of chloro- hydrins in aqueous solutions and in Lvater-soluble solvents-Le., alcohols, glycols, etc.-in concentrations varying from 2 to lOO7i0 chlorohydrin. The total grams of chlorohydrin present in the

Table I. Composition of JIixtures I I1 I11 IT' v VI VI1 % % % % % % %

Ethylene chlorohy- drin 5 . 3 5 . 3 5 . 3 5 . 3 3 0 . 2 6 8 . 0 5 . 3

Propylene chlorohy- drin 2 . 6 2 . 6 2 . 6 2 . 6 1 4 . 2 3 2 . 0 2 . 6

Ethylene dichloride 0 0 0 . 7 0 . 5 0 0 0 . 5 Pro ylenedichloride 0 0 0 . 3 0 . 2 0 0 0 . 2 Dicgloroethvlene 0 1 . 0 0 0 . 2 0 0 0 . 2 Dichloroisopropyl-

Hydrochloric acid 0 0 0 0 0 0 3 . 4 8 Water 9 2 . 1 9 1 . 1 91 1 91 1 55 6 0 8 7 . 6 2

ethylene 0 0 0 0 . 1 0 0 0 . 1

Chlorine from inorganic compounds Theory 0 0 0 0 0 0 3 . 3 9 Found 0 0 0 0 0 0 3 . 3 4

Theory 3 . 3 2 3 . 3 2 3 . 3 2 3 . 3 2 18 .62 42 .00 3 . 3 2 Found 3 . 2 8 3 . 3 0 3 . 3 5 3 . 3 1 18 .49 42 .06 3 . 3 1

Theory 0 0 .50 0 . 6 9 0 . 6 3 0 0 0 . 6 3 Found 0 0 . 4 9 0 . 7 0 0 . 6 1 0 0 0 . 6 4

Chlorine from chlorohydrin

Chlorine from aliphatic chlorides

V O L U M E 20, NO. 1, J A N U A R Y 1948 69

hydrolysis mixture must not exceed approximately 0.26 gram moved by some method such as distillation, or the chlorohydrin (calculated as ethylene chlorohydrin), This sample size is limited extracted with water. by the amount of chloride which can conveniently be titrated with 0.1 .V silver nitrate. (1) Francis. F . . “Notes on Orrrnnic Chemistrv.” D. 174. London.

LITERATURE CITED

-~ It is not feasible to analyze chlorohydrins dissolved in water-

insoluble solvents by this method. The presence of excess water- insoluble solvent prevents the reaction Xvith the aqueous alkalies

Edward Arnold and Co., 7935. ( 2 ) Scott, W. D., “Standard Methods of Chemical Analysis,” Vol. I,

5th ed., p. 272, New York, D. Van Nostrand Co., 1939. (3) Uhrig, K., IND. EXG. CHEM., A N . ~ L . ED., 18, 469 (1946).

and yields lo\\ results. For such solutions the solvent murt be re- R~~~~~ ED june 23 1947

Fluorine Content of Certain Vegetation in a Western Pennsylvania Area

H. V. CHURCHILL, R . J. ROVLEY, AND L. N. MARTIN

.4luminum Research Laboratories, .Yew Kensington, P a .

In the Pittsburgh area unexpectedly large amounts of fluorine are to be found in the foliage of trees and in grass, alfalfa, and other vegetation. There seems to be a marked tendency towards increased concentrations of fluorine as the growing season progresses. As leaves grow old they have a higher fluorine content. It is also possible that fluorine accumulates on the surface of leaves as tluorine- bearing dusts, because of long exposure to the atmosphere. Foliage samples taken in the autumn may show higher fluorine contents because of in-

1 R E C E S T years there has been manifested an increasing in- I terest, in the conipounds of fluorine as important industrial materials. This commercial and indust’rial interest in fluorine compounds has been paralleled by a widespread study of the oc- currence of fluorides in municipal and domestic waters. This latter phase of the probleni found its inception in a publication by the senior author ( 1 ) . A rather complete study of the problem of fluorine in potable waters is contained in a publication of the -1nierican Geographical Society (3). Interest in the fluoride con- tent of waters has led to studies of the occurrence of fluorine compounds in various forms of plant and vegetable life. In the present paper are presented analytical data covering the presence of fluorine in tree leaves and ot,her forms of vegetation, chiefly in the Pittsburgh district.

These dat,a are reported as parts per niillion based on the dry weight of samples. In brief, the analytical procedure was as follolvs:

.\ portion of each sample of leaves was oven-dried to constant weight at a temperature of 105” C. and the percentage of mois- ture in the sample was calculated. The sample for fluorine analysis was weighed from the undried portion of the sample, since it \\-as felt that some fluorine compounds might be lost in the drying proctbss. The dry weight of the sample actually used was calculated. The sample was covered with lime TF-ater and taken to dryness on a hot plate, with maintenance of caustic alkalinity by lime additions throughout the operation. The dried alkaline residue rvas ignited a t a temperature of 500” to 550” C. The entire ash !vas used for the determination of fluorine. The fluorine was isolated by the well-known Willard-Winter dis- tillation process 14) and its concentration was measured by tho- rium nitratc titration, using sodium alizarin sulfonate indicator.

Most of the samples here reported were taken in an area north- east of Pittsburgh; all locations mentioned are in Pennsylvania

crease in atmospheric fluorine occasioned by in- crease of coal smoke in the air during the early autumn, but this is probably a minor factor. The presence of fluorine in coal would indicate that fluorine might well have been a normal constituent of the ligneous or organic material from which coal was derived. There appear to be two sources from which plants may absorb fluorine-soil and atmos- phere. The presence of fluorine in soils is well rec- ognized and coal smoke is an important source of air-borne fluorine.

except as indicated. Table I lists fluorine contents of various samples of tree leaves. Fluorine as used in this paper should he construed as meaning fluorine combined as fluoride-Le., fluorine as hydrofluoric acid, calcium fluoride, sodium fluoride, etc.-in no case do the authors mean elemental fluorine as such. In Table I each tree which was sampled is numbered. Letter5 in parentheses indicate separate samples from the same tree.

The condition of the foliage was normal. The data give clear evidence that fluorine is a normal constituent of vegetation in western Pennsylvania. It seems obvious that fluorine, a t least to the extent herein reported, may be present in vegetation n-ith- out shon-ing any evidence of attack or deterioration. In further evidence that no deterioration had occurred is the fact that dur- ing the years covered by the taking of samples, all the fruit trees sampled bore normal crops. hIost of the trees sampled have never been sprayed with fluorine-bearing insecticides, but some trees had been sprayed with fluorine-bearing material in years previous to the years of sampling covered by the data in the tables.

-111 trees and vines sampled a t each location \vere located on the same plot of ground, and care was taken to obtain a rcpresen- tative and average sample of the foliage. -111 the leaves sampled were in good condition and had the normal appearance of leaves for the season of sampling.

One interesting aspect revealed by the data in Table I is the apparent increase in fluorine content of leaves as they grovi older. I n connection with this it is interesting to note the data on the fluorine content of grass from the Aluminum Research Labora- tories’ lawn at S e w Kensington, as given in Table 11. The lawn was mowed weekly and cuttings were not removed but served to mulch the soil. Fresh cuttings were taken as samples on the dates given in the table.