I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
November 1948
2163
The activation energy calculated in Figure 18 for this photorelaxation is 5.7 kcal., which is a low value characteristic of lightactivated chemical reactions. This value should be considered as only semiquantitative because we are not certain of the homogeneous penetration of light through these samples.
32
3.I
The fact that the relaxation process is photoactivated is another indication that relaxation in these polysulfide rubbers is essentially chemical in nature, as light would not be expeoted to have any effect on a physical process such as viscous flow. ACKNOWLEDGMENTS
The authors wish to thank J. Patrick, F. 0. Davis, E. Fettes, and G. P. Roeser for many invaluable discussions. They also acknowledge the cooperation of the Thiokol Corporation which made this research possible. In addition, the authors wish to thank R. D. Andrews for critically reviewing the manuscript of this paper. I
01
I I
LITERATURE CITED
IO
I TIME (hours)
Figure 18. . Calculated Stress Relaxation of Latex Sheet A Due to Light Alone, a t Different Temperatures 0 40° C., Q 60° C., 0 80' C., Ewt 5.69 koal.
-
aonstant for the li ht-activated reaction. Dividing Equation 2 by 1, we obtain t%e curve of decay of relative stress due to the light-activated reaction alone f l j o = exp ( -kit)
(3)
(1) Andrews, R.D.,Tobolsky, A. V., and Hanson, E. E., J . Applied Phys., 17, 352 (1946). (2) Blatz, P. J., and Tobolsky, A. V., J. Chem. Phya., 14, 113 (1946). (3) Green, M.S., and Tobolsky, A. V., Ibid., 14,80 (1946). (4) Stern, M.D., and Tobolsky, A. V., Ibid., 14,93(1946). (6) Tobolsky, A.V., andilndrews, R. D., Ibid., 13,3 (1945). (6) Tobolsky, A. V., Prettyman, I. B., and Dillon, J. H., J. Applied Phys., 15,380 (1944). RECEIVED June 5 , 1947. Presented before the Division of Rubber Chemistry a t the 111th Meeting of the AXERICANCHBMICAL SOCIETY,Atlantic City, N. J.
Color Contamination of Petroleum Products Transported by Pipe Line L. V. SORG AND R. E. DICKEY Standard Oil Company (Indiana), Sugar Creek, Mo. T h e field trial of an experimental alkaline corrosion inhibitor in a pipe-line system handling finished petroleum products, ranging from motor fuels to burning oils, gave rise to a most unexpected color contamination problem, which was most noticeable and objectionable in the case of water-white products such as kerosene. The dye responsible for this discoloration of water-white products was isolated and identified as p-indophenol. This dye is formed in the strongly alkaline corrosion-inhibitor phase and results from a reaction between an oxidation product of the antioxidant used in motor fuels and phenol, naturally occurring in petroleum stocks. These compounds are concentrated by the alkaline inhibitor phase. Concentrations of p-indophenol as low as 1 part in 5,000,000 were found to impart an objectionable pink discoloration to water-white petroleum products. It was found that the addition of sodium sulfite to the corrosion inhibitor would eliminate the color difficulty without affecting the corrosion-inhibiting quality of the inhibitor.
A
INTERNAL corrosion inhibitor ( I ) , consisting of an aqueous solution containing approximately 3% sodium hydroxide, 6% ammonia, and a wetting agent, has been used in a field trial to protect a petroleum products pipe-line sys#,em originating a t Sugar Creek, Mo., and extending to Des Moines,
Iowa, and Sioux Falls, S. D. I n the trial of this inhibitor, an unforeseen difficulty developed which caused the petroleum products to become color-contaminated during pipe-line residence, especially during the winter season when the antioxidant concentration in motor fuel was relatively high. This discoloration was particularly undesirable in water-white products which became pink in color when contaminated. To obviate this difficulty, a n investigation was pursued which concluded with the separation and identification of the offending dye and the development of a modified corrosion-inhibitor formula which prevented color contamination over practical distances of pipe-line transportation. SEPARATION AND IDENTIFICATION OF T H E COLOR CONTAMINANT
Spent inhibitor removed from the pipe line was observed to be deep blue in color and, when present at p H values above 12.5, did not impart upon contact any color to water-white products. At lower p H values, a pink color was imparted to water-white products, the depth of color increasing as the pH value passed through neutrality into the acid range. It, therefore, appeared that the offending dye formed, a t highly alkaline p H values, a sodium salt which was oil-insoluble. At neutrality and in the acid range, the salt no longer existed, but the free dye appeared and was oil-soluble. It was further observed that the deep blue
2164
INDUSTRIAL AND ENGINEERING CHEMISTRY 141
Vol. 40, No. 11
-
SrANDARD
-
SUGAR CREEK
COUNClL
INHIBITOR
USE
IN
PO COUNCIL B L U f f S AND DTS MOINES
BLUFFS
PO SIOUX F A L L S
--. SUGAR
CREEK
0 BURLINGTON
7 4
- COUNCIL BLUFFS
JC%
COUNCIL BLUFFS
- OES MOINES
- SIOUX
FALLS
? f
YEAR
/94c
Figure 1.
+ NaOH -+
KaO-
-0 __
-KI-IGHQ
n-Butyl-p-aminop henol
Naturally occurring phenol 2.
Oxidation of n-but~-l-~-amino~henol t o p-nitrosophenol.
NaO--CZ)--NHCaHo
4- 0 2 -+ NaO- (II>-w=o p-Nitrosophenol (sodium salt)
3. p-Kitrosophenol undergoes a tautomeric shift. SaO-a--S=O
3
4
1948
Sediment Removals on the Western Products Pipe Line
color could be developed synthetically by mixing alkali, phenol, and a common gasoline antioxidant, n-butyl-p-aminophenol, and spreading it out in thin films to provide access to oxygen. The synthetic dye so obtained, when brought to neutmlitv, imparted a pink color to water-white petroleum products nhich then possessed the same Lovibond color as that orruriing during pipe-line transportation. Based on the above data, it appeared most logical that the contaminating color was the result of p-indophenol ( 4 , 6). The following mechanism was postulated for its formation: 1. FJxtraction of phenols by the all--I\:HCIHg
2
S a O - N =a = O Quinone oxime (sodium salt)
4. The quinone oxime couples with phenol to form p-indophenol.
-id-
o = = ~ = s
p-I ndophenol (sodium salt) The first step postulates the extraction of n-butyl-p-aminophenol and naturally occurring phenol from the petroleum products by the alkaline corrosion-inhibitor phase. The antioxidant comes specifically from motor fuel to which it is added to retard gum formation. The amount of antioxidant thus removed must be very small since no significant decrease in the stability of motor fuels contacted with the alkaline corrosion inhibitor has been observed. Also, as will be shown later, the actual concentration of dye developed in the pipe-line products is extremely small. The phenol is thought, to be extracted principally from kerosene fractions which are known t o contain it. While other phenols are present in kerosene fractions, only monohydroxybenzene enters into the above reaction to produce a color contamination identical t,o tJhatobserved. The sodium salt of n-butyl-p-aminophenol oxidizes to p-nitrosophenol in the second step and undergoes a tautomeric shift t o quinone oxime in the third step, In the final reaction the quinone ,oxime combines with sodium phenoxide t o yield pindophenol.
November 1948
INDUSTRIAL AND E N G I N E E R I N G CHEMISTRY
Based on the above postulated mechanism, effort was directed toward the isolation of p-indophenol from spent inhibitor which had been removed from the pipe line. After acidifying the spent inhibitor, the free dye was adsorbed on Tripoli powder from which it was extracted with ether. The material obtained was very impure and required extensive purification, which was made difficult because of the very small amount of dye obtained. A free dye of fair purity was obtained by precipitation from a benzeneligroin mixture as small, dark red crystals. The final free dye product was identified by making the leuco base (2)and the acetylated compound (3) as derivatives. Table I presents the data upon which the confirmation was established. As indicated, the leuco base and acetyl derivative had melting points which compared acceptably with those reported in the literature. No definite melting point was obtainable on the free dye because of decompasition.
TABLE I. PHYSICAL PROPERTIES OF p-INDOPHENOL EXTRACTED FROM PIPE-LINEPRODUCTS Solubility HC1 NaOH NazCOa Benzede Ethyl aoetate Ligroin Organic solvents Acid Strong alkaline solutions p-Indo henol Leuco gase Aoetyl derivative
Reported S S
Found S
S
81.8
s1.s
Ins.
Ins.
S
S
Color in Solution Red Red Red Red Blue Blue Melting Point, C. Over 100, indefinite D 129 (1) 174.5 ( I ) 175 115-16 (8) 114
SYNTHESIS OF p-INDOPHENOL AND COMPARISON WITH PIPELINE DYE
To obtain data for comparison with the dye isolated from spent pipe-line inhibitor, p-indophenol was prepared synthetically by use of the quinone chlorimide synthesis (a). The steps in this reaction are shown as follows: 1. Preparation of quinone chlorimide.
HO-O-NH: + O= NaOCl-+
p-Aminophenol
==N-Cl
Quinone chlorimide
2165
TABLE11. LOVIBONDCOLOR^ OF KEROSENECONTAINING pINDOPHENOL
a
Synthetic p-Indophenol P. p. m. Yellow Red 16.0 10 15.0 1 3.5 2.0 0.5 2.2 1.1 1.2 0.6 0.2 0 0.6 0.2 6-inch cell.
Kerosene Colored in Pipe Line Yellow Red 16.0 15.0 1.7 3.2 2.2 1.0 1.2 0.6 0.6 0.2
The close agreement between the Lovibond color analysis of the synthetically contaminated oil and the product actually contaminated during pipe-line transportation substantiates the conclusion that the offending dye is p-indophenol. DEVELOPMENT OF A MODIFIED INTERNAL CORROSION INHIBITOR
The preparation of the colorless leuco base from p-indophenol by reduction indicated an approach to obviating the color contamination of petroleum products transported through the pipe line. The use of sodium sulfite (6) as a reducing agent for effectively controlling the color-contaminating properties of pindophenol was explored in a field trial during 1946. The sulfite was incorporated directly into the alkaline pipe-line-inhibitor formula to the extent of 2%, equal to about 0.6 pound per 1000 barrels of oil pumped. The sulfite was found to have no adverse effect upon the corrosion-protection properties of the inhibitor. The presence of the sulfite not only converted any occurring p-indophenol to a colorless leuco compound, but also combined with oxygen, thereby minimizing the formation of p-indophenol. This latter reaction is responsible for consuming the sylfite, SO that periodic reinjection of sulfite solution is dictated. The leuco compound appeared to be much more stable than the p-indophenol since oxidation to regenerate the dye was not observed on water-white products after removal from the pipe line. The value of sodium sulfite in combating color contamination from p-indophenol is evidenced by data shown in Table I11 for samples taken a t milepost 104. The color contamination existing before using sodium sulfite in the inhibitor formula is shown in the first part of the table, and comparative data for samples taken after injection (including the added sulfite) are given in the last part of the table.
2. Condensation of quinone chlorimide with phenol.
TABLE111. EFFECTOF SODIUMSULFITEON THE COLORExTRACTED BY KEROSENE FROM PIPELINE INHIBITOR Date
O = ~__ = - N - L ~ O N s p-Indophenol
A yield equivalent to 13.5% of the theoretical was obtained. The sodium salt of p-indophenol was separated as very small, green crystals which were water-soluble and imparted a very deep blue color to the solution. Physical properties of synthetic p-indophenol agreed with those obtained for the free dye isolated from pipe-line spent inhibitor. An attempt was made to evaluate the concentration of pindophenol which would produce color contamination of waterwhite kerosene to the extent observed in the pipe line. Table I1 presents data on the Lovibond colors of samples of kerosene transported through the pipe line and contaminated with pindophenol. Comparative data on the synthetic dye concentration required to obtain an equivalent color are also shown in this table. When the Lovibond color reaches a red value of 0.6, a water-white product is visibly pink. Thus a p-indophenol concentration of only 1 part in 5,000,000 is sufficient to impart objectionable pink color contamination to water-white products.
Lovibond Yellow
Lovibond Red
1. Samples Taken before Injection of Sodium Sulfite 3- 4-45 3-25-45
4- 4-45
2.0 6.0 0.8
1.0 3.6 0.3
2. Samples Taken after Injection of Sodium Sulfite 1-27-46 0.2 0.7 2- 7-40 0.2 0.7 0.1 2-16-46 0.6 2-25-46 0.1 0.5
These data show that water-white kerosene transported through the pipe line in the presence of a n alkaline pipe-line inhibitor modified by the addition of sodium sulfite was not contaminated with the objectionable pink color characteristic of dilute solutions of p-indophenol. The Lovibond colors indicated for the 1946 field trial are normal for the color of kerosene as produced a t the refinery. At distances close to 250 miles, without sulfite reinjection, some color contamination appeared. However, the intensity of the color was much less pronounced than it had been without the use of sodium sulfite.
2166
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 40, No. 11
CONCLUSIOh'S
LITERATURE CITED
The color contamination of pet,roleurn products transported through a pipe line in the presence of an alkaline corrosion inhibitor has been traced to the formation of p-indophenol. The postulated reaction yielding p-indophenol has been substantiated by separation of a dye from spent corrosioii inhibitor and its identification as p-indophenol. The dye was found to impart sufficient objectionable color a t concentrations as small as 1 part in 5,000,000. The adverse effect of p-indophenol was obviated by the modification of the internal corrosion inhibitor to include sodium sulfite which reduced the dye to the colorless leuco base and minimized dye formation.
(1) Anderson, A. A. (t,o Standard Oil Co.), U. 6. Patent 2,422,516
(June 17, 1947).
( 2 ) Gibbs, H. D., Hall, W. L., and Clark. VV. AT., U . 5'.Pub. Health Depts. S u p p l . , KO. 69 (1929). (3) Heller, G., Anrz. 392,1 6 4 8 (1912). (4) McElvain, S.M., "Characterization of Organic Compounds," p .
120, Xew York, Macinillan Co., 1945. (5) Sorg, L. V., U. 8. Patent Application, Serial 652,173 (March 5, 1946). (6) Wahl, A, and Atack, F. W., "Manufacture of Organic Dyestuffs," p. 237, London, G. Bell and Sons, 1914. RECEIVEDJuly 1, 1947. Preaented before the 16th Xidwest Regional Meeting of the AMERICAN CHEMICAL SOCIETY, Kansas CiBy, Mo.
SUPERFRACTIONATI N STUDIES Naphtha f r o m Santa Barbara, Venezuela, Crude Oil F. G. SCHWARTZ, R . 31. GOODIIL'Gl, AND B. H. ECCLESTOY Petroleum Experiment Station, Bureau of Mines, Bartlesuille, Okla.
A
naphtha from a Qdnta Brrbira, \ cnczueln, crude oil was superfractionated, 0.5% fractions were collected, and both CRC-F-2 (clear) and CRC-F-3 (4.0 ml. of tctraethyllead per gallon) octane numbers were determined for each fraction. A plot of the octane numbers against sum per cent distilled indicates boiling points at which cuts can be wade on refinery superfractionations, and the effect on resulting product. Analyses of the 0.570 fractions, with their engine ratings, provide data for calculating the blending octane numbers of individual hydrocarbons blended with other hydrocarbons with which they normally are associated. These blending octane numbers may be used to calculate the octane numbers of naphthas having a boiling range of 97 O to 243' F., using laboratory superfractionations and refractometric analyses. (Above this boiling range the methods of analysis used malie composition indeterminate, except as to type of hydrocarbon. Some values are given for type hydrocarbons up to 320" F.) The data derived from superfractionation of naphtha from Santa Barbara confirm and supplement data previously reported, Data from these superfractionations include both Composition of naphtha and octane numbers of gasoline deriFed from crude oils studied.
T
HE refiner using modern fractionation equipment t o produce a maximum of gasoline must consider the effect of each addi-
tional increment of naphtha upon the octane number of the gasoline produced. Closely cut fractions, produced a t the maximum efficiency of the fractionators, are necessary to ensure maximum production of gasoline a t a specific octane number level. TO permit calculation of octane numbers of incremental portions of riapht,has the Bureau of Alines has superfractionated selected naphthas into 0.5% fractions and determined their composition and octane numbers, so that blending octane numbers for the component hydrocarbons can be computed. These blending octane numbers are also helpful in evaluating naphthas as gasoline stocks. Often the volumc of naphtha available, such as that distilled from a 1-gallon sample of crude oil, is only sufficient to permit determination of the octane number for the naphtha, and little is left for the number of other tests that may- be de1
Present a d d r e w Bureau of Nines, Washington, D. C.
sired. However, if the compo.itiori of the naphtha, which can be determined on a small sample, and the blending octane numbers of the component hydrocarbons are known the octane number of the entire sample or any portion of it can be calculated. Procuring such data was the objective of studies reported here. The preceding mtirle in this series (6) described the equipment and the procedure used in studying an Oklahoma City naphtha and included calculated CRC-F-3 (I.S.T.M. U614-46T) octane numbers with 4.0 ml. of tetraethyllead per gallon for hydrocarbons present in the boiling range of 97" to 258 O F. The present article describes a similar study of a naphtha from Santa Barbara, Venezuela, crude oil and presents calculated blending octane numbers by the CRC-F-2 (A.S.T.X. 11357-46) method, clear, and by the CRC-F-3 method with 4.0 ml. of tetraethyllead per gallon for hydrocarbons in the boiling range of 97' to 326 F. APPARATUS AND PROCEDURE
The naphtha from Santa Barbara crude oil was supeifractionated in the equipment previously described-an electrically heated batch still with a 55-gallon stillpot and a 25-foot column packed with 3 / 3 2 inch steel helices and having an efficiency equivalent to 80 theoretical plates a t total reflux. The naphtha as received consisted of four separate successive cuts made in the refinery. Inspection data on each cut are given in Table 1 and
TABLBI. PROPERTIES OF REFINERY CUTS FROM SANTA BARBARA, VENEZUELA, S a P H T H A Property
Drum 1 7.61 34.4 0.0756 77.9 80
99 147
183
198
0.5
4.7 TABLE
IT.
PROPERTIES OF
Gravity, OA.P.1. Sp. gi:., 60:/60" P. Bromine h o, Initial b.p.. F. evapd., F. 00% erayd., F. 90% evapd., F. E n d point, F.
58.4
0.7450 Negative 97 1.51
250 319 360
Drum2 2.74 12.4 0.7786 50.2 208 212 213 217 22 1 0.6 0.4
Drum3 10.22 46.2 0,7777 50.5
Drum 4 1.55
7.0
0.7989 45.6 290 316 332 853 372 0.8 0.2
25Q
267 282
321
361 0.9
0 4
NAPHTHA CHARGED
TO
Residue, vol. % Losa, vol. % Reid vapor press., Ib. Sulfur wt % F-2 0.". iolear) F-2 0.5. (3 mi. TEL/!zal.) Corrosion Doctor test
STILL 0.8 1.2 6.1 0.012 59.6 78.4 Positive
Sour
