Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1994-04-12
1997-12-16
Cintins, Marianne M.
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C07C 4100
Patent
active
056987471
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/EP92/01875 filed Aug. 14, 1992.
This invention relates to ethers, especially to ethers suitable for use in load bearing compositions, e.g., drilling fluids, and to a process for their manufacture.
Drilling of oil or gas wells normally involves the circulation of a fluid through the drill string and out through nozzles in the drill bit, the fluid being returned through the annular passage formed between the drill string and the bore. The fluid cools and lubricates the drill, provides a hydrostatic head to counterbalance pressures, and removes the cuttings from the drill bit. Such fluids are also employed in other areas, for example, geothermal drilling, drilling for water and scientific drilling.
Oil-containing drilling emulsions have been used for many years for these purposes. The emulsions may be in the form of a water-in-oil or an oil-in-water emulsion, in each case normally having finely divided solids suspended therein, and containing a variety of additives for various purposes, e.g., emulsifiers, surfactants, pH control agents, biocides, corrosion inhibitors, weight an viscosity regulators, oxygen and sulphur scavengers, and fluid-loss additives.
The oil traditionally used was a hydrocarbon oil, often with an aromatic content; concern for the environment has recently required hydrocarbon oils used for the purpose to be largely aliphatic and more recently, because aliphatic hydrocarbons are not readily biodegradable, hydrocarbons are being increasingly restricted in their use. Many replacements for hydrocarbons have been suggested; these have primarily been aliphatic materials with functional groups that facilitate biodegradation, for example, ester groups. Esters are, however, likely to be saponified in use, causing odour, viscosity and caking problems in the drilling fluid.
In our co-pending European Patent Application No. (Case 91PINT008), we describe drilling fluids in which the oil phase comprises certain aliphatic ethers, which in one embodiment are derived from an alcohol obtained by hydroformylating an olefin feedstock and hydrogenating the resulting aldehyde. The alcohol is converted to an ether over an acid catalyst, and such a manufacturing process produces an ether containing ester impurities as a result of reaction between the alcohol and the acid catalyst. The esters can hydrolyse during use and cause degradation of the drilling fluid.
When acid catalyst are used in ether synthesis as described above, the catalyst is neutralized after completion of the reaction by sodium hydroxide or carbonate, followed by washing with water to remove the organic and inorganic salts formed. This procedure at best only partially hydrolyses the residual esters present and, to obtain ester-free ethers, the product must be distilled. With certain catalysts, however, the ester is not completely separated from the ether even by distillation.
There accordingly remains a need for a process for removing ester contaminants from an ether obtained by acid catalysed conversion of an alcohol.
The present invention provides a process for removing an ester impurity from an ether which comprises treating the ester-ether mixture with a metal salt of an alcohol.
The present invention also provides a process for the manufacture of an ether by acid-catalysed reaction of at least one alcohol wherein after reaction the ether-containing reaction mixture is treated with a metal salt of an alcohol.
The metal is advantageously an alkali or an alkaline earth metal, preferably sodium or potassium.
The metal salt is advantageously a salt of a monohydric alcohol, e.g., an alkanol, preferably an alkanol having 1 to 6, especially 1 to 4 carbon atoms, for example ethanol, propanol, butanol, pentanol or hexanol, but advantageously methanol. (The salt may be a salt of the alcohol that has been converted to the ether.) Of alcohols having isomers, the primary isomer is preferred.
The metal salts of alcohols are referred to subsequent herein for brevity as alkoxides.
The purification process is effective to re
REFERENCES:
patent: 4230892 (1980-10-01), Pruckmayr
Perron et al., Bulletin De L Societe Chemique de France, p. 334, col. 1, line 17--col. 2, 1949.
Godwin Allen David
Mathys Georges Marie Karel
Cintins Marianne M.
Exxon Chemical Patents Inc.
Jones Dwayne C.
Jordan Richard D.
Mahon John J.
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