the present invention is a method for making high purity oximes using an aqueous hydroxylamine solution and ketones . the examples given below use acetone , acetyl acetone ( 2 , 4pentanedione ), and cyclohexanone to yield acetone oxime , acetyl acetone dioxime , and cyclohexanone oxime , but the method has also been used with methyl ethyl ketone , methyl isopropyl ketone , methyl isobutyl ketone , and cylcopentanone to yield the corresponding oximes . of these examples , only acetone requires acidification , as discussed below . when acidification is required , preferably a high purity organic acid such as formic , acetic , citric , or oxalic acid is used . inorganic acids , such as hydrochloric , sulfuric , nitric , or phosphoric acids , may be used but may lead to unwanted ionic or inorganic contaminants . those skilled in the art will recognize that analogous ketones may be used to create other oximes . 50 ml of high purity acetone was added to 100 ml of high purity 50 % hydroxylamine / 50 % water ( percentages by weight ), and stirred with a magnetic stirrer . the mixture was left to reach equilibrium by sitting a few hours to reach ambient temperature ( approximately 25 ° c .). 50 ml of 98 % formic acid in water was then added to the mixture to yield a ph of 6 . 0 - 6 . 2 , and mixed to reach equilibrium . crystalline acetone oxime separated . the mixture was stirred for 24 hours at ambient temperature to complete formation of crystals and filtered the next day . the acetone oxime was purified as follows : the crystals were filtered and then dissolved in a non - polar solvent ( perfluorocyclohexane ) by heating , and cooled overnight at ambient temperature for recrystallization . the crystalline material was then filtered and washed with perfluorocyclohexane . the melting point was 61 ° c .- 63 ° c ., and the yield 85 %- 90 %. the product was analyzed by ft - ir , gc / ms , nmr , and other methods to confirm the molecular structure . the crystal structure was determined by x - ray methods . the product is believed to be formed by the following reaction : table 1 illustrates yields when different acids are substituted for formic acid . the acids were added to achieve a ph of 6 . 0 to 6 . 2 , and otherwise the reaction conditions were the same as in example 1 . 50 ml of high purity acetyl acetone was gradually added to 100 ml of high purity 50 % hydroxylamine / 50 %. water in a glass beaker , and stirred with a magnetic stirrer overnight at ambient temperature . crystalline acetyl acetone dioxime separated . the crystals were filtered and purified as in example 1 . 54 g of crystals were obtained , melting point 140 - 144 ° c ., yield 83 %. formation is believed to occur as follows : 50 ml of high purity cyclohexanone was gradually added to 100 ml of high purity 50 % hydroxylamine / 50 % water in a glass beaker , and stirred with a magnetic stirrer overnight at ambient temperature . crystalline cyclohexanone oxime separated . the crystals were filtered and purified as in example 1 . 55 g of crystals were obtained , melting point 86 - 900 ° c ., yield 95 %. formation is believed to occur as follows : the above examples illustrate synthesis of oximes at close to 100 % yields , without addition of contaminating salts or acids . although the present invention has been described above in terms of a specific embodiment , it is anticipated that alterations and modifications thereof will no doubt become apparent to those skilled in the art . it is therefore intended that the following claims be interpreted as covering all such alterations and modifications as fall within the true spirit and scope of the invention .