Texaco Inc.

Ethyl Additives Corporation

Tze-Chi Jao

William J Powers, Iii

Leonard A Matthews

Brian L Papke

Jayne M Vaccaro

Kenneth L Kreuz

Edward R Arndt

A method of preparing a calcium sulfonate having at least a TBN of 500 where the method comprises reacting CaO, Ca(OH).sub.2 and H.sub.2 O, and synthetic monoalkylbenzene sulfonate and synthetic dialkylbenzene sulfonate in certain molar ratios, respectively, for a sufficient length of time to produce the overbased calcium sulfonate.

Overbased calcium sulfonate

A continuous method of preparing an overbased calcium sulfonate which comprises repeating the following steps until a desired TBN is obtained, said method comprising: (a) contacting Ca (OH).sub.2 and methanol with a normal calcium sulfonate hydrocarbon solution to solubilize at least a portion of the Ca(OH).sub.2 ; (b) filtering the sulfonate solution to separate and remove the non-solubilized Ca(OH).sub.2 from the solubilized Ca(OH).sub.2 contained in an obtained sulfonate filtrate; (c) treating said sulfonate filtrate with gaseous CO.sub.2 to convert the solubilized CA(OH).sub.2 to solubilized CaCO.sub.3 ; (d) blowing said solubilized CaCO.sub.3 with an inert gas to remove therefrom any excess CO.sub.2 and the aqueous phase generated therein to obtain an overbased sulfonate liquid; (e) adding more of said normal calcium sulfonate solution to said overbased sulfonate liquid and contacting said overbased sulfonate liquid with said non-solubilized Ca(OH).sub.2 and additional fresh Ca(OH).sub.2 to obtain an overbased sulfonate liquid product; (f) repeating steps (b) through (e) until the desired TBN of the sulfonate liquid product is obtained, and removing an amount of sulfonate liquid product after step (d) equal to the additions of normal calcium sulfonate and Ca(OH).sub.2 in step (e); and (g) stripping the methanol and hydrocarbon solvent from the sulfonate liquid removed after step (d) to obtain the overbased calcium sulfonate product.

Continuous process for preparing overbased salts

In the preparation of an overbased calcium sulfonate, it has been found that adding the calcium hydroxide during the carbonation reaction reduced solid waste. An initial charge of 15 to 25 wt % of the total calcium hydroxide is added to initiate the carbonation reaction. The balance is added by a process whereby calcium hydroxide concentration remains low in the reaction admixture to reduce amorphous calcium carbonate residence time. In the process, calcium hydroxide is added in amounts whereby the molar ratio of carbon dioxide to the sum of calcium hydroxide and calcium oxide is about 0.8.

Process for preparing overbased calcium sulfonates

In the preparation of an overbased calcium sulfonate, it has been found that charging calcium oxide and the total amount of water in amount of water of 20 to 25 mole % of the calcium oxide and a calcium oxide:calcium hydroxide ratio of 60:40 before carbonation improved feedstock utilization and reduced solids. Calcium hydroxide may be mixed with the calcium oxide through it takes no part in the water requirement.

In an overbased sulfonate process calcium hydroxide is formed in situ by first adding 25% of the total water and then adding the remainder of the water uniformly to the calcium oxide over the entire hydration and carbonation time rather than incrementally. It has been found experimentally that by first adding at least 25% of the total water in a single aliquot that crystalline calcium carbon formation is suppressed. A 300 TBN product is formed with an H.sub.2 O/CaO molar ratio of 0.4 and a 3 hour hydration time. A 400 TBN product is formed with an H.sub.2 O/CaO molar ratio of 0.8 and 3 hour hydration time. Improved storage stability is achieved by eliminating crystalline calcium carbonate formation. Crystalline calcium carbonate has been related to engine wear.

Growing community of inventors

Fishkill, NY, United States of America

Tze-Chi Jao