I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
1120
Vol. 16, No. 11
EFFECTS OF REFINING AGENTSON PUREORGANICS U L ~ UCOMPOUNDS R DISSOLVED IN NAPHTHA NAPHTHA SOLD TIONS
Mercaptans
Alkyl sulfides Alkyl disulfides Thiophene Hydrogen sulfide Carbon disulfide Sulfoxides Sulfones
&SO4 Forms soluble disulfides
Dissolves these readily Dissolves these fairly readily Forms soluble thiophenesulfonic acid Converts to HnO and S Dissolves sparingly Dissolves these readily Dissolves these readily
Free sulfur
+
NaaPbOa Forms partially soluble lead mercaptides
NazPbOz S Forms soluble diPbS sulfide
No effect
No effect
CUO Removes as copper mercaptides on moderate heating No effect
N o effect
No effect
No effect’
Noeffect
No effect
No effect
No effect
No effect Converts it to HzO and S Removes as NazC03 and NazSOr No effect
+
Removes as P b S
Removes as P b S
No effect
No effect
No effect
No effect
No effect
No effect
No effect
No effect
No effect in cold. Forms PbS on heating
No effect in cold. Forms PbS on
EFFECT OF ANHYDROUS ALUMINIUM CHLORIDE ON MERCAPTANS-DesUlfUriing E$ect. The following results were obtained in the closed system, using Stock Solution A at room temperature: No.
1 2 3
4
1
Sulfur in treated naphtha Per cent 0.45
AlCIs Grams
2 4 6 8
0.32
.
0.15 0.016
AlCls Forms addition compounds in the cold which decompose on heating
No effect
Same as above ’
Same as above Decomposes i t on heating
No effect No effect
heating
doctor treatment, but the other compounds studied were apparently not affected.
Time Hours 1 1 1
NaOCl Forms soluble disulfides
DOCTOR TEST Positive Positive Positive Positive
Nature of Desulfurizing Action. A mixture of 3 grams of isobutyl mercaptan, 100 cc. of petroleum ether, and 15 grams of aluminium chloride were placed in a Kjeldahl flask and aliowed to stand for 12 hours with occasional shaking. The petroleum ether layer was then decanted and the aluminium chloride residue washed several times with a fresh supply of petroleum ether. The flask was then placed in an ice bath and 100 cc. of petroleum ether were added. Chopped ice was next added to the aluminium chloride residue until the decomposition was complete. The petroleum ether layer was decanted and evaporated on the steam bath. The residue gave the doctor test for mercaptan. An experiment with a series of gas-washing bottles showed that no hydrochloric acid was evolved a t room temperature. E$ect of Heat. A mixture of 12 grams of aluminium
chloride, 25 cc. of naphtha, and 50 cc. of Stock Solution A was distilled until 50 cc. of the distillate was collected. A copious evolution of hydrogen sulfide was observed throughout the distillation. The recovered naphtha contained 0.11 per cent of sulfur. Hydrogen sulfide and mercaptans were present. A consideration of these results indicates that the desulfurizing action of aluminium chloride a t ordinary temperature is due to the formation of addition compounds and at higher temperatures is due to cracking, most of the sulfur being eliminated as hydrogen sulfide. ON ALKYLSULFIDES AND ALKYLDIsULFIDEs-Quantitative experiments similar to those above indicate that aluminium chloride forms addition compounds at ordinary temperature but a t higher temperatures cracking takes place and hydrogen sulfide is evolved in large quantity and some mercaptans are formed. ON THIOPHENE-Quantitative experiments indicate that aluminium chloride does not form addition compounds with naphtha solutions of thiophene a t ordinary temperatures. At higher temperatures cracking takes place resulting in the evolution of hydrogen sulfide and the formation of mercaptans. Consideration of these results indicates that when a sulfur gasoline is cracked, hydrogen sulfide an.d mercaptans are among the sulfur compounds formed. The presence of hydrogen sulfide mercaptans probably accounts for the fact that some cracked distillates are odorous and sour and can be effectively refined by the doctor treatment.
A Confirmatory Test for the Presence of Diethylphthalate in Specially Denatured Alcohol’ By E.A. Vuilleumier DICKINSON COLLEGE, CARLISLE, PA.
O R M U L A 39-B, Appendix of Regulations No. 61, Bureau of Internal Revenue, calls for the addition of 2.5 gallons of diethylphthalate and 3 pints of benzene to 100 gallons of pure ethyl alcohol. Diethylphthalate is a colorless, odorless oil, practically insoluble in water, and has a boiling point of 290’ C. and a specific gravity of 1.123. The usual qualitative test for this denaturant depends upon its conversion into phenolphthalein or fluorescein. The nature of this test is such that a confirmatory method is desirable. 1 Received
September 15, 1924.
, The ethyl alcohol and benzene in a 50-ml. sample may be eliminated by evaporation on the water bath. The residue is washed with water, is transferred to a test tube, and a convenient quantity of a salt solution, made by dissolving 20 grams of sodium chloride in 100 ml. of water, is added. The diethylphthalate will float on this solution. Water is now cautiously added to the contents of the tube, until the droplets of diethylphthalate neither sink nor rise when the tube is shaken. When the salt solution has been adjusted to the same density as the droplets, the specific gravity of t4e. solution is determined by any of the usual methods.
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