Dispersant for coal into oils

DETAILED DESCRIPTION OF THE INVENTION As a result of extensive researches made for overcoming the drawbacks of the conventional coal-mixed fuels and for developing a dispersant capable of affording a coal-oil mixed fuel which is prevented from precipitation and dense deposition of coal in holding tanks in tanker vessels or in field storage tanks and is easily unloaded from holding tanks in the tanker vessels or discharged from the field storage tanks, it has now been found that a coal-oil mixed fuel possessing excellent stability and fluidity for a long period of time can be obtained by dispersing finely pulverized coal into a fuel oil by the aid of a composite surface active agent comprised of a mixture of a metal salt of a dialkylsulfosuccinate and a lower aliphatic alcohol.
This invention has been accomplished on the basis of the above finding.
In the present invention, a dispersant for coal into oils which contains: (a) a metal salt of a dialkyl sulfosuccinate of the general formula: ##STR1## wherein R.
sup.
1 and R.
sup.
2 each represent an alkyl group with at least 4 carbon atoms, n represents an integer of 1.
about.
3 and M represents a metal having a valency of n, and (b) at least one lower aliphatic alcohol selected from the group consisting of a monohydric alcohol having 1.
about.
5 carbon atoms, a polyhydric alcohol having 2.
about.
5 carbon atoms and an alcohol with 2.
about.
5 carbon atoms having an alkoxy group with 1.
about.
5 carbon atoms, is used for obtaining a coal-oil mixed fuel excellent in both stability and fluidity and capable of being advantageously transported by a mammoth tanker or stored in a large field tank.
In the constituent (a) of the dispersant, i.
e.
a metal salt of a dialkyl sulfosuccinate of the above general formula, R.
sup.
1 and R.
sup.
2 are preferably alkyl groups having at least 4, especially 6.
about.
12 carbon atoms and M is a metal with a valency of 1.
about.
3, preferably Li, K, Na or Ca but may be Al, Mg and Ba.
Illustrative of the constituent (a) are: dihexyl sodium sulfosuccinate, di-n-octyl potassium sulfosuccinate, bis-2-ethylhexyl sodium sulfosuccinate, bis-2-ethylhexyl potassium sulfosuccinate, bis-2-ethylhexyl aluminum sulfosuccinate, di-n-decyl sodium sulfosuccinate, di-n-dodecyl calcium sulfosuccinate, and di-lanoline alcohol sodium sulfosuccinate