Patent GB-821397-A (GB)
Title: Improvements in or relating to the preparation of oil soluble basic salts of organicacids
Inventor: CAMPBELL JAMES
IPC: C10M159/20
Filed: 1957-11-18
Abstract: An oil solution of a basic oil-soluble metal salt of an organic acid is prepared from an impure oil solution of an oil-soluble metal or ammonium salt of an organic acid by acidifying said oil solution, treating the oil solution of the organic acid so formed with a neutral water-miscible oxygen-containing organic solvent, removing the suspended solids, and either (a) reacting the oil solution of the organic acid with excess metal base, or (b) reacting the oil solution of the organic acid with a metal base and then reacting the oil-soluble salt of the organic acid so formed, in the presence of said oil and a neutral water-miscible oxygen-containing organic solvent, with an oil-insoluble metal compound formed in situ in the reaction mixture.  The oil-insoluble metal compound is preferably formed in situ by reacting the oil solution of the organic acid after removal of suspended solids with excess metal base and then treating the reaction mixture with an acidic compound such as CO2.  The basic oil-soluble metal salt may be isolated from the oil solution, e.g. by distilling the oil, and may then be dissolved in a different oil. The neutral water - miscible oxygen - containing organic solvent is preferably chosen from aliphatic alcohols, glycols or ketones containing not more than 6 carbon atoms, such as methanol, ethanol, ethylene glycol or acetone, but others such as ethers, e.g. diisopropyl ether, methyl and ethyl ethers of ethylene glycol, 1,3-dioxane or 1,4-dioxane, and esters, e.g. ethyl lactate, may be used.  The solvent may contain minor amounts of acidic or basic material.  The acid used in the acidification step is preferably inorganic, e.g. sulphuric acid, but may be an organic acid containing 3 or less carbon atoms, e.g. propionic or acetic acid.  The term "oil" is used to mean a neutral liquid which is not miscible with water such as liquid hydrocarbons, e.g. benzene, toluene, xylene, pentane, heptane and petroleum fractions from gasoline up to lubricating oils.  If a suitable oil is used in the reaction, the product may be added directly to a lubricating oil.  The products after removal of the oil used during the reaction may be incorporated in synthetic lubricants such as polymerised olefins, alkylated aromatic hydrocarbons, polysiloxanes, fluorocarbons or esters or fatty oils.  Specified starting material organic acid salts include sodium, potassium, ammonium or polyvalent metal salts of sulphonic (e.g. petroleum sulphonic), carboxylic (e.g. aromatic or naphthenic) and phosphorus-containing or phosphorus- and sulphur-containing acids. The basic salts prepared in the invention may contain ammonium, monovalent metals such as sodium, potassium, or lithium, or polyvalent metals such as the alkaline earth metals (especially calcium and barium), magnesium, zinc, lead, aluminium, copper, tin, cobalt, nickel and manganese.  The oil-insoluble metal compound formed in situ is preferably a carbonate, but may be, for example, a sulphide, sulphite or salt of an organic acid containing not more than 3 carbon atoms.  In an example, a xylene solution of impure sodium alkyl salicylates (C14-18 mono- and dialkyl salicylates) is prepared by reacting a xylene solution of the corresponding alkyl phenates with CO2 under pressure; the solution is acidified with H2SO4, separated and methanol added to the xylene solution, followed by settling and filtering; the filtrate is mixed with a Ca(OH)2/xylene slurry and a centrifuge sludge from a later stage, more methanol is added and CO2 passed in; the methanol layer is removed and the xylene layer centrifuged, the sludge being recycled as above; the xylene is distilled, spindle oil is added to the residue and the solution is centrifuged and filtered.  Specifications 786,167 and 818,326 are referred to.ALSO:An oil solution of a basic oil-soluble metal salt of an organic acid is prepared from an impure oil solution of an oil-soluble metal or ammonium salt of an organic acid by acidifying said oil solution, treating the oil solution of the organic acid so formed with a neutral water-miscible oxygen-containing organic solvent, removing the suspended solids, and reacting the oil solution of the organic acid either with excess metal base or with a metal base and reacting the oil-soluble salt of the organic acid so formed in the presence of said oil and a neutral watermiscible oxygen-containing organic solvent, with an oil-insoluble metal compound formed in situ in the reaction mixture. The oilinsoluble metal compound is preferably formed in situ by reacting the oil solution of the organic acid after removal of suspended solids with excess metal base and then treating the reaction mixture with an acidic compound such as CO2.  The basic oil-soluble metal salt may be isolated from the oil solution, e.g. by distilling the oil, and may then be dissolved in a different oil. The neutral water-miscible oxygen-containing organic solvent preferably boils below about 140 DEG  C.  It is preferably miscible with water in all proportions although solvents miscible with up to about 10% or at least 50% by volume of water are mentioned. Preferably aliphatic alcohols, glycols or ketones containing not more than 6 carbon atoms are used such as methanol, ethanol, ethylene glycol or acetone, but others such as ethers, e.g. diisopropyl ether, methyl and ethyl ethers of ethylene glycol, 1,3-dioxane or 1,4-dioxane, and esters, e.g. ethyl lactate may be used.  The solvent may contain minor amounts of acidic or basic material.  The acid used in the acidification step is preferably inorganic, e.g. sulphuric acid but may be an organic acid containing 3 or less carbon atoms, e.g. propionic or acetic acid.  The neutral water-miscible oxygen-containing organic solvent added to the acidified oil solution of the oil-soluble metal salts of the organic acid may be added in amounts of 3-100, preferably 8-20% by weight based on the oil solution, more preferably in a quantity just sufficient to saturate the oil solution with the solvent.  The same solvent is preferably present during the reaction with the oil-insoluble metal compound formed in situ, but the first solvent may be separated after the solids have been removed and another or the same solvent added later. In any case a further quantity of the same or a different solvent may be added before the final step.  Preferably, a further quantity of the same solvent is added after the oil solution of the organic acid has been reacted with a metal base, preferably in an amount such that the total neutral water-miscible oxygen-containing organic solvent present when the oil-soluble salt of the organic acid is reacted with the oil-insoluble metal compound formed in situ is 3-100%, preferably about 30-50% by weight based on the oil solution of the oil-soluble salt of the organic acid. Preferably, a minor amount, more preferably 5-10% by weight of water, is also present during this stage.  The term "oil" is used to mean a neutral liquid which is not miscible with water such as liquid hydrocarbons, e.g. benzene, toluene, xylene, pentane, heptane and petroleum fractions from gasoline up to lubricating oils.  If a suitable oil is used in the reaction, the product may be added directly to a lubricating oil.  The products after removal of the oil used during the reaction may be incorporated in synthetic lubricants such as polymerized olefins, alkylated aromatic hydrocarbons, polysiloxanes, fluorocarbons or esters or fatty oils.  The final oil solution should preferably be centrifuged and filtered.  Specified starting material organic acid salts include sodium potassium, ammonium or polyvalent metal salts of sulphonic, carboxylic and phosphorus-containing acids. The basic salts prepared in the invention may contain ammonium, monovalent metals such as sodium, potassium, or lithium, or polyvalent metals such as the alkaline earth metals (especially calcium and barium), magnesium, zinc, lead, aluminium, copper, tin, cobalt, nickel and manganese. The oil-insoluble metal compound formed in situ is preferably a carbonate, but may be, for example, a sulphide, sulphite or salt of an organic acid containing not more than 3 carbon atoms.  Generally, temperatures of 20-150 DEG  C. and pressures of atmospheric or higher are used. After the reaction, the reaction mixture may be freed from water and/or the water-miscible oxygen-containing organic solvent, e.g. by heating to 135-160 DEG  C. and may be air-blown.  The products may be used as lubricant additives or for the preparation of biocides or paint dryers or catalysts.  In an example, a xylene solution of impure sodium alkyl salicylates (C14-18 mono and dialkyl salicylates) is prepared by reacting a xylene solution of the corresponding alkyl phenates with CO2 under pressure; the solution is acidified with H2SO4 separated and methanol added to the xylene solution followed by settling and filtering; the filtrate is mixed with a Ca(OH)2/xylene slurry and a centrifuge sludge from a later stage, more methanol is added and CO2 passed in; the methanol layer is removed and the xylene layer centrifuged, the sludge being recycled as above; the xylene is distilled, spindle oil is added to the residue and the solution is centrifuged and filtered. Specifications 786,167 and 818,326 are referred to.