US1972760A - Gum inhiritor for hydrocarbon fuels - Google Patents

Description

Patented sept l, 1934 ATE-M oFncI-z our: mum-r0: ro'a nxbnocaanon wan No Drawing. mm, use,

sanctum I'm (1144-0) This invention relates to improvement in means for the protection of liquid hydrocarbm products against discoloration and formation of insoluble and products, and more particularly to 5 improved materials for use with unsaturated liquidhydrocarbons whlchmaybeusedasfuels.

Liquid hydrocarbons as produced, particularly when prepared by the distillation or cracking of petroleum, poss us a tendency to discolor onstandingandtoform gumsand resinous by the modern crac are extremely complicated mixtures comprising many constituents, the character of these constituents and the relative proportions of different constituents depending upon thesourceofthecrudeandthepartlcularcrack ing processemployed. Besides the normal and branchedchainthereareoftenpresent tial percentages of aromatic hydrocarbons. Thecrudecrackedgasolinealsoalways contains lmsaturated such for example as oleilnes and diolennes. Although theremaybepresentsomedscontaining a triple bond, these are probably not compounds suchasmaybeformedbythepolymerizationof acetylene, but rather suchcompounds asmaybe formed by the isomerization of dienesandhaving thegeneralformmaCnH-wheremisgmater thann, but lessthan 2n+2. Theseunsaturated compoundsinthepresenceofairarecapableof oxidation toform a series of products, some of which are resinous or gummy. The dioleflnes, andmoreunsaturatedhydrocarbons,areparticularly easily oxidised. Differences in structure otherthanthedegreeofunsaturatlon'causeconsiderable variation in the tendency to oxidise, butingeneraltheeaseofoaidatlonincreases wlththedegreeofunsatm'atlon. Themorerecentpressuremethodsofvaporphase cracking result in a considerably higher percentage of dioleflnes than the older methods, and it has been statedthatthesepmductsmayrlmashighas -8to15% inimreflned gasoline.

Ithasbeentotreatthecrudeproducts resulting from the more'recent cracking at; insomemannertoremovethegreater part of these more highly unsaturated products. Amongthesemethodsoftreatmentmaybementioned the sulfuric'a'cid treatment and the fullr; earthvaporphasetreatment. Whiiethese methods of pm'lilcationmay removethe greater partofthehighlyumaturated compolmds, it is 'foundthatmanybrandsof'gasolinetendtodis- .coloronstorageandtoformacertainamount if ofglnn. Thegumappearstobeacomplexmixture of polymerized hydrocarbons, resins, acids, aldebydes, ketonm and peroxides. Its formation is distinctly detrimental in all cases. For example, the deposition of gum in gasoline gives a sticky substance which deposits upon the walls and hot- 00 tom of the container, and which may cause serious trouble if formed or deposited in the fuel system of internal combustion engines. The soluble portion of the gum is also objectionable because of the introduction of a non-volatile com- 88 ponent into the gmdline.

Our invention has for an object the inhibition of the formation of these insoluble guns and resins, with an attendant improvement in the quality of the hydrocarbon and freedom from the To difllculties introduced by the formation of the more or loss insoluble and sticky, gummy material, such as irregular flow in the fuel and lubricating systems of internal combustion A further object is to make it possible to'use as 73 an internal combustion fuel, liquid hydrocarbons such as gasoline, that contain larger amounts of highly unsaturated compounds than commerciallyusedatpresent. Aproductofthissortcanbe producedata1owercost,an was cases, improved anti-knock properties.

We have found that by treating hydrocarbon fuels such asgasoline, and specifically cracked gasoline or gasoline which has a tendency to form gum, the gum formation can be very appreciably g5 inhibited if the hydrocarbon fuel is treated with a diaryl guanidine. More specifically, our invention relatestotheuseasguminhibitorsforhydrocarbon fuels of compolmds of the type represented by w NHB NH-O/ inwhichRisani y groupand'R'isanaryl group whichmaybe the sameas or different from-R, and in which both R and B may con- 21 an inhibitor developed much color and contained a large amount of gum. The sample protected by the diorthotolyl guanidine, on the other hand,-

developed'n'o color and showed little, if any, increase in the amount of dissolved gum. It will be understood that the example given above has of the substances which we have found to be effective inhibitors are: diphenyl guanidine, diorthotolyl guanidine, di-para-tolyl-guanidine, dixylyl-guanidine and phenyl-tolyl-guanidine.

In some cases it has been found advisable to use a mixture of guanidine rather than a single pure product. It has been found in some cases that a combination of two difierent guanidines is superior in its effect on gasoline to either guanidine used singly.

We may use higher or lower concentrations of any members of the class of'compounds represented by the general formula given hereabove, and to secure marked inhibition of gum formation although, of course, the degree of inhibition will vary depending upon the individual guanidine, the concentration of guanidine employed, and the nature of the hydrocarbon fuel. In general, amounts of from 0.0001 of 1% to 0.05- of 1% of inhibitor will be found sufficient for the grades of gasoline at present on the market. It will be obvious, of course, that these percentages may be varied within wide limits. Obviously, our invention is of great importance in freeing internal combustion engines from the annoyance and'improper functioning due to the deposition of gum in the fuel system and explosion chamher.

As many apparently widely different embodiments of this invention may be made without departing from the spirit thereof, it is to be understood that we do not limit ourselves to the fore-= going examples or descriptions except as indicatedin the following patent claims:

We claim:

1. A motor fuel comprising cracked gasoline normally tending to form gum containing, as a gum inhibitor, 2. small amount of a substance of the type:

in which R is an aryl group and R is an aryl group which may be the same as R.

2. Gasoline produced by the cracking ofpetrov leum oils containing, as a gum inhibitor, a small amount of a substance of the type:

3. A motor fuel comprising cracked gasoline normally tending to form gum containing, as a gum inhibitor, a small amount of a substance of the type NHR NH=C NHR'

in which R and R represent alkyl substituted.-

aryl groups,

5. A motor fuel comprising cracked gasoline normally tending to form gum. containing, as a gum inhibitor, a small amount of a substance of the type NHR wherein R and R1 represent aryl groups at least one of which contains an alkyl group substituted therein.

7. A motor fuel comprising cracked hydrocarbon distillates normally tending to deteriorate and form gum on storageand containing, as a gum inhibitor, a small amount of a substance.

having the following general formula NHR NHR;

wherein R represents an aryl group and R1 rep- I resents an aryl group which may be the same as R.

8. A motor fuel comprising cracked hydrocar- 1 bon distillates normally tending to form gum and containing, as a. gum inhibitor, a small quantity of a substance having the following general formula NHR wherein R and R1 represent phenyl groups at least one of which contains an alkyl group substituted therein.

9. A motor fuel comprising cracked gasoline obtained by vapor phase conversion of high boiling hydrocarbons, normally tending to deteriorate and form gum, and containing as a gum inhlbitor a small proportion of-a diaryl guanidine.

10. A motor fuel comprising cracked hydrocarbon dlstillates normally tending to form gum d 5 containing, as a gum inhibitor, a small amount of di-para-tolyl guanidine.

11. A motor fuel comprising cracked gasoline normally tending to deteriorate and form gum and containing, as a gum inhibitor, a small amount of di-para-tolyl guanidine'.

12. A cracked hydrocarbon distillate containing high percentages of unsaturated compounds combined with a gum inhibitor in the form of diphenylguanidine.

13. A cracked hydrocarbon motor fuel contain ing diphenylguanidine in quantities sufficient to inhibit the formation of gums in said fuel.

14. A cracked hydrocarbondistillate having substantially the boiling range of ordinary gasoline and having added thereto a gum inhibitor in the form of a compound containing diphenylguanidine.

15. The method of treating cracked petroleum distillates obtained by vapor phase conversion of high boiling hydrocarbons, which consists inadding to such distillates a compound containing diphenylguanidine in quantities suftlcient toinhibit the natural evolution of resinous compounds of such distillates.

16. A cracked, highly unsaturated hydrocarbon motor fuel distillate of less-readily detonating type normally tending to, develop gum forming constituents, containing diphenylguanidine in quantity suflicient to prevent development of substantial quantities of such gum forming constituents.

17. The method of stabilizing the characteristics of a cracked, unsaturated hydrocarbon motor i'uel distillate ot the less-readily. detonating type,normally tending to deteriorate and develop gum-forming constituents, which comprises adding thereto prior to'such deterioration a small proportion of diphenylguanidine, sufli-. cient to substantially inhibit further gum formation in said distillate.

18. A motor fuel comprising cracked gasoline normally tending to form gum containing, as a guminhibitor, a small amount of di-orthotolyl guanidine.

19. Gasoline produced by the cracking of petroleum oils containing, as a gum inhibitor, 9. small amount of di-ortho-tolyl guanidine. 4 7 WILLIAM S. CALCOTI.