US2250501A - Treatment of hydrocarbons - Google Patents

Description

y 1941- R. H. ROSENWALD EI'AL 2,250,501

TREATMENT OF HYDROCARBONS Filed April 30, 1938 FIG. l

20 25 TOTAL ALKYL CARBON ATOMS IN SUBSTITUTING GROUPS vw qmq '.OOOO

OLLVU BOJJEIHNI ZALLDBJJH ATTORNEY mean Jul 29, 1941 UNITED STATES TREATMENT or mnocannons Robert H. Rosenwald and Joseph nomine s,

Chicago, Ill., assignors to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application April so, 1938, Serial No. 205,356

3 Claims.

This invention relates more particularly to a process of treatment applicable to lower boiling fractions of cracked distillates within the gasoline range although it is also applicable to heavier distillates produced by the fractionation of cracked products and to corresponding fractions irom'the primary distillation of crude petroleums or other hydrocarbonaceous materials such -,as coal and shale.

The process is concerned specifically with the use 01 certain definite types of inhibitors to ma- ,tions leading to the formation of higher boiling polymers and resinous products which cause the deterioration of Ithe gasoline in respectto color,

gum contentland antiknock value is stopped tor a time depending upon the eiliciency of the inhibitor, the degree of unsaturation of the oil and the extent oi its exposure. It is'recognized that the inhibitor art is know to include the use of such compounds as phenols, amines, and aminophenols and crude primary products containing these compounds, and, no

basic claim is made herein to the broad use of any of these classes. The present invention is specially concerned with a limited group of compounds which have been found to possess exceptionally good inhibiting potency combined with resistance to accidental removal by contact with water or caustic soda which .occurs at many points in the storage systems of oil refineries.

- In one specific embodiment the present invention comprises the treatment or unstable gaso;

lines, particularly cracked gasolines, to materially arrest the deterioration thereof by adding to said gasolines relatively small percentages of N-di-alkyi aminophenolsin which the substituting alkyl groups are ditlerent. The alkyl. groups may be of a normal or branched character and I the substituted amino group may be in the ortho,

meta, or para position with respect to thehy- .droxyl group although in general the compounds of greater potencyi'all within the general class those oi thepara substituted variety.

' -We have shown as a result of considerable number oi experiments in which differently substituted alkyl aminophenols were tested that greater advantages are gained by utilizing as inhibitors alkyl amino-phenols in which there is substitution of both amino hydrog'ens by difierent alkyl groups over utilizing those characterized by substitution with identical groups or by substitution of one amino hydrogen with one group even though-the total number of carbon atoms in the substituting groups is the same in all cases. The advantages gained include'greater,

inhibiting potency, greater solubility in gasolines and improved resistance to extraction with water or alkaline solutions tb which gasolines may be exposed during storage conditions, on account of the decreased solubility oi the mixed ,sub-

stituted compounds. These advantages were unexpected and unpredictable from any study 01 chemical composition or constitution relating to inhibitors and form the principal subject matter of the present invention. The actual de ree of these effects willbe indicated in a-succeeding illustrative and numerical section. Compounds of the present character are made from amino phenols by successively replacing the amino hydrogens with the desired alkyl groups.

"These stepwise substitutions are made generally by the interaction of molal proportions of an amino-phenol with an alkyl chloride or an alkyl sulfate using an alkaline condensing agent according to the following equations which show the manufacture of N-methyl-n-iso-amyl paminophenol:

H H 0 0 I iso-CsHnCl :2 I nor H-NH H-N C5Hn p-amino isoamyl N-isoamyl-p-amlno phenol chloride phenol 40 li-H01 H-N-l CsH n methyl N-methyl-isoamylchloride 'p-amino phenol In this method the reaction may be brought about in a solvent such as ethyl alcohol and it is desirable to have present ear-amount of a carbonate or bicarbonate molecularly equivalent to the amount of alkyl halide. A catalyst is not necessary.

The following specific example is given of the manufacture or a,compound falling within the a scope or the invention, the method shown being definitely applicable to the manufacture of other so similar compounds by varying, the alkyl' groups in the reactants according to their relative molecular weights.

To prepare N n octyl N methyl-p-aminophenol; the mixture tabulated below was refluxed with various types of antiknock compounds such as tetra ethyl lead and with special types or inhibitors which are directed to the preservation of color or other specificpropcrties.

for 12 hours under atmospheric pressure. The following tabulation includes one set-of Parts by weight data obtained in connection with the type of th I h no] Sulfate 45 compounds which characterize the present ini Y g g g 52 vention. This set of data includes the effect on if 3 45 the copper dish gums and the oxygen bomb stag I 200 bility of a gasoline to which 0.01% of the inhibia tors were added.

Copper'dish gum, Qxygen bomb stability, Percent removed Emotive mg./100 cc. u induction eriod, min. by- Inhitbiitor re 0 Water Caustic Water Caustic Water Causti wash wash wash wash wash wash Original gasoline 37 218 106 85 85 N mfietliyl-N-butyl-p-amino- 1 78 4 7 75 eno N nethyl-Nf-isoamyl-pamino- 325 290 105 87 phenol 1.51 7 15 v s 320 285 105 15 81 N-methyl-N-octyl-p-amino- V phenol 1- 10 7 7 i0 335 330 310 0 6 N-methyl-N-lauryl-p-ammo- 1 phenol 0- 50 2 9 13 $90 425 405 0 0 After the period of digestion the total reactants were poured'into water and the aqueous and oil layers were extracted with a small volume of ether. Ether extracts were then heated to volatilize the ether and then distilled under an absolute pressure of 4 mm. of mercury. The primary distillation gave the results shown below Parts by Boiling weight range C. Fraction I 2. 5 120-167 Fraction II- 32. 9 168-170 Residue 5. 0

'N-n-octyl-N-metbyl-p-aminophenol.

centages of the order of 0.01% are sufficient.

Since the present compounds are considerably more soluble in gasoline than those in which the alkyl groups are the same, the addition of the necessary small amounts to gasoline-contained in large storage tanks is more simple and more easily effected than when inhibitors of lesser solubility are employed in which cases it is frequently necessary to employ a long period of mechanical mixing or an auxiliary solvent to assist in the dispersion of the inhibiting compounds. In the present instance a minimum of mixing is required and solvents are not necessary. In addition, owing to the relatively low water and alkali solubility of the preferred compounds, they may be used in gasolines which are not dry or which are stored over water or alkali to prevent corrosion of the tank bottoms. These inhibitors may be also employed in conjunction with other compounds of specific character such as the dyes which are frequently used to mask the slightly yellow tinge characteristic of cracked gasolines,

Ill

fected by water or caustic washing'since therewas no material change in the copper dish gum or the oxygen bomb stability of the gasolines to which they were added.

The attached curves designated as Figure I are introduced to exemplify the more general aspects of the invention. These curves were made up to indicate the data obtained in a large number of experiments, Referring to the figure, it will be seen that curve#1 shows the variation of the eifective inhibitor ratio with the total carbon atoms in substituting groups of mono-alkyl substituted aminophenols. Curve #2 shows the same relationship when di-alkyl substituted conipounds are considered in which the substituting groups are the same. Curve #3 whichit will be observed is higher than the other two-at all points below 18 carbon-atoms shows graphically the data obtained with mixed alkyl substituted aminophenols. From this data it is obvious that the most efi'ective inhibitors are those di-substituted' aminophenols in which the substituting r groups are different.

We claim as our invention:

I 1. A process for the treatment of gasolines sub- '3. Motor fuel comprising unstable gasoline conof N-methyltaining a relatively small amount -butyl-p-aminophenol.

ROBERT H. ROSENWALD. JOSEPH A. CHENICEK.

The effectiveinhibitor ratio given in'column 1 calculated on a,

Images