Preparation Of Hydroxylamine Salts From The Acid-catalyzed Hydrolysis Of Cyclohexanone Oxime And Modeling Of Solubility Of Hydroxylamine Salts

Hydroxylamine salts(including hydroxylamine nitrate,hydroxylamine hydrochloride,hydroxylamine sulfate and hydroxylamine phosphate)are widely used in various chemical fields such as pesticides,medicines,and analysis.In particular,hydroxylamine nitrate,as a special type of high-energy oxidant,demonstrates its unique advantages in the fields of aerospace propulsion and nuclear waste treatment,and which is expected to replace hydrazine hydrate as a new green liquid propellant.At present,the preparation processes of hydroxylamine salts include the raschig process,the catalytic reduction process,the acid cleavage of nitroalkanes and the electrolysis reduction process,et al.However,there are many problems in these processes,such as cumbersome preparation process,excessive by-product,high energy consumption and serious environmental pollution.Therefore,in this article,a new route for the preparation of hydroxylamine nitrate and hydroxylamine hydrochloride by hydrolysis of cyclohexanone oxime was proposed by combining the cyclohexanone ammoximation process and the reaction-extraction coupling technique.The solubility of hydroxylamine hydrochloride and hydroxylamine sulfate in acid system was determined,and the solubility model was established,which can provid the thermodynamic theoretical foundation for the preparation,crystallization and purification of hydroxylamine salt.The preparation of hydroxylamine nitrate by acid-catalytic hydrolysis of cyclohexanone oxime was studied in this thesis,the effect of extractant on the hydrolysis reaction was emphatically investigated,and the coupling reaction conditions were optimized.The results showed that when cyclohexane was used as the reactive extractant,at 70°C,the mole ratio of H~+to cyclohexanone oxime was2:1,the volume of water was 100 mL,the volume ratio of water to oil is 1:1,and the reaction time is 1 h,the conversion of cyclohexanone oxime can reach 53.76%with98.5%of selectivity to cyclohexanone and 98.0%of selectivity to hydroxylamine nitrate;With dichloroethane as the extractant,at 74°C,the mole ratio of H~+to cyclohexanone oxime was 2:1,the volume of water was 125 mL,the volume ratio of water to oil is 1:1,and the reaction time is 1 h,the conversion of cyclohexanone oxime can reach 79.3%with the selectivity to cyclohexanone and hydroxylamine nitrate up to 99%.Using dichloroethane as extractant,at the room temperature,the continuous hydrolysis-extraction coupling reaction were investigated.After three circulation of aqueous solution,the conversion of cyclohexanone oxime is about80.9%.In addition,we studied the preparation of hydroxylamine hydrochloride by hydrolysis of cyclohexanone oxime by reaction-extraction coupling technique,the results showed that dichloroethane was used as the extractant,at 74°C,the mole ratio of H~+to cyclohexanone oxime is 3:1,the volume of water is 100 mL,the volume ratio of oil to water is 1.5:1,and the reaction time is 1 h,the conversion of cyclohexanone oxime can reach 86.6%with the selectivity to cyclohexanone and hydroxylamine nitrate was over 98%.Finally,the solubility of hydroxylamine sulfate and hydroxylamine hydrochloride in acidic system was determined,and the solubility curve for temperature and acid concentration was obtained.By correlating the experimental values with some solubility models,it is found that the the solubility calculated by the model shows good agreement with the experimental data.It can provide references and direction for the separation and purification of solid hydroxylamine sulfate production.