Organic compounds -- part of the class 532-570 series – Organic compounds – Sulfonic acids or salts thereof
Reexamination Certificate
1999-12-21
2001-05-29
McKane, Joseph K. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Sulfonic acids or salts thereof
Reexamination Certificate
active
06239309
ABSTRACT:
The present invention relates to a process for using sludge produced during the production of either a high BN overbased alkylaryl sulfonate or an overbased sulfurized alkylphenate to produce overbased alkylaryl sulfonate or overbased sulfurized alkylphenate.
BACKGROUND OF THE INVENTION
Commercially, sulfonic acid is reacted with lime, methanol, xylene, carbon dioxide, and calcium hydroxide to produce a high BN overbased alkylaryl sulfonate. The high BN sulfonate is often passed through a centrifuge to remove sediment. For every 10,000 metric tons of sulfonate final product produced, there is about 900 metric tons of sludge residue. That sludge residue (a cake) comprises about 20% lime and calcium carbonate, about 20 to 25% high BN overbased alkylaryl sulfonate with calcium carbonate dissolved in the sulfonate, and about 55% solvent (e.g., xylene). For the time being, this sludge residue is burned, which is not desirable economically or environmentally.
A similar problem results, to some extent, in the production of a commercial overbased sulfurized alkylphenate, which produces a similar sludge residue that is normally burnt. In a typical commercial process, an alkylphenol is reacted with sulfur, lime, and glycol, preferably associated with a mono alcohol, in the presence of a low overbased sulfonate and diluent oil, then the product is overbased with carbon dioxide. The production of such an overbased sulfurized alkylphenate is described in British patent 1,015,769.
SUMMARY OF THE INVENTION
The present invention is based upon work trying to provide a better use of the sludge residue. The invention provides for treatment of that sludge residue to produce overbased alkylaryl sulfonate or overbased sulfurized alkylphenate.
Recycle of the sludge to the bottom of the reactor, where the high BN
Recycle of the sludge to the bottom of the reactor, where the high BN overbased alkylaryl sulfonate is produced, would not work because the solubility of the resulting sulfonate would be poor because of accumulation of impurities.
If the sludge from the production of high BN overbased alkylaryl sulfonate is passed through a decanter, the centrate contains high BN overbased alkylaryl sulfonate, xylene, and about 1% to 3% sediment, and the residue from the decanter is a concentrated sludge. Recycle of the centrate back to the centrifuge would not work because the resulting final high BN overbased alkylaryl sulfonate would have solubility problems.
We have developed processes for using the sludge formed in the preparation of a high BN overbased alkylaryl sulfonate to produce additional high BN overbased alkylaryl sulfonate. That sludge comprises high BN overbased alkylaryl sulfonate, alkaline earth metal salt, alkaline earth metal base, and other impurities. The processes depend, in part, on how the sludge has to be separated from high BN overbased alkylaryl sulfonate.
If centrifugation is needed to separate the sludge from high BN overbased alkylaryl sulfonate, then the sludge is passed through a phase separation system (e.g., decanter) to form a lower density fraction (e.g., centrate) and a higher density fraction (e.g., filtrate). The lower density fraction has high BN overbased alkylaryl sulfonate and reduced levels of alkaline earth metal salt, alkaline earth metal base, and other impurities. The higher density fraction has increased levels of said alkaline earth metal salt, alkaline earth metal base, and other impurities. If centrifugation is not needed to separate the sludge from the high BN overbased alkylaryl sulfonate, then the use of the phase separation system is not necessary.
If a phase separation system is used, the lower density fraction coming from that phase separation system is treated with an acidic reactant. On the other hand, if no phase separation system is used, the sludge is treated with an acidic reactant. In both cases, the acidic reactant (preferably alkylaryl sulfonic acid) eliminates the big large particle size alkaline earth metal salt by converting it into calcium sulfonate. At least one equivalent of acidic reactant is used for each equivalent of alkaline earth metal salt. For instance, if the acidic reactant is an alkylaryl sulfonic acid then at least two moles of acid must be used per mole of alkaline earth metal salt, since the salt is divalent while the acid is monovalent. Preferably, this step is carried out in the presence of a mixture of methanol and xylene.
The treated product is then reacted with an excess of alkaline earth base, and preferably with alkylaryl sulfonic acid, and preferably either in the presence of a mixture of methanol and xylene or in the presence of chloride ions and a carboxylic acid containing 1 to 4 carbon atoms, to produce a reaction product containing additional high BN overbased alkylaryl sulfonate and additional sludge.
If the original sludge is filtered, instead of centrifuged, and if there is no decanting step, then the additional high BN overbased alkylaryl sulfonate should be filtered.
The process depends, in part, on how the process incorporates the sludge and how impurities are eliminated.
In one case, where centrifugation is needed to separate the sludge from high BN overbased alkylaryl sulfonate, the sludge is treated with an acidic reactant, preferably alkylarylsulfonic acid, eventually in presence of a methanol and (or) xylene. For instance, if the acidic reactant is an alkylaryl sulfonic acid then at least two moles of acid must be used per mole of alkaline earth metal salt, since the salt is divalent while the acid is monovalent. At least one equivalent of acidic reactant is used for each equivalent of alkaline earth metal salt. The treated product is then reacted with an excess of alkaline earth base and preferably with alkylaryl sulfonic acid in the presence of chloride and a carboxylic acid containing 1 to 4 carbons atoms to produce a reaction product containing low BN overbased alkylarylsulfonate and additional sludge which is filtered.
Similarly, we have developed processes for using the sludge formed in the preparation of an overbased sulfurized alkylphenate to produce additional overbased sulfurized alkylphenate. That sludge comprises overbased sulfurized alkylphenate, alkaline earth metal salt, alkaline earth metal base, and other impurities. The processes also depend, in part, on how the sludge has to be separated from overbased sulfurized alkylphenate.
Like in the processes described above, if centrifugation is needed to separate the sludge from the overbased sulfurized alkylphenate, then the sludge is passed through a phase separation system to form a lower density fraction and a higher density fraction. The lower density fraction has overbased sulfurized alkylphenate and reduced levels of alkaline earth metal salt, alkaline earth metal base, and other impurities. The higher density fraction has increased levels of said alkaline earth metal salt, alkaline earth metal base, and other impurities. If centrifugation is not needed to separate the sludge from the overbased sulfurized alkylphenate, then the use of the phase separation system is not necessary.
Like in the processes described above, the lower density fraction (if centrifugation is needed) or sludge (if centrifugation is not needed) is treated with an acidic reactant, preferably alkylaryl sulfonic acid, to reduce the average particle size of the alkaline earth metal salt by converting it into calcium sulfonate. At least one equivalent of acidic reactant is used for each equivalent of alkaline earth metal salt. For instance, if the acidic reactant is an alkylaryl sulfonic acid, then at least two moles of acid must be used per mole of alkaline earth metal salt, since the salt is divalent while this acid is monovalent. This step can be carried out in the presence of methanol and/or xylene.
The treated product is then reacted with alkylphenol, sulfur, and an excess of alkaline earth base, preferably in the presence of a glycol, and more preferably in the presence of a glycol and either 2-ethylhexanol or decyl alcohol, to produce a reaction product con
Chevron Oronite S.A.
McKane Joseph K.
Murray Joseph
Sheridan Richard J.
Stumpf Walter L.
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