用椰子油直接合成烷基羟肟酸及应用研究

以椰子油和盐酸羟胺(NH2OH.HCl)为原料,以NaOH为催化剂,采用羟胺-椰子油法直接合成了烷基羟肟酸。通过对合成产品进行Fe3+定性检测和对产品及椰子油进行红外光谱分析,证实产品含有烷基羟肟酸。研究了原料摩尔比、肟化反应温度、催化剂NaOH滴加速率、肟化反应时间对产品中羟肟酸质量分数的影响。得到优化反应条件为:n(椰子油)∶n(NH2OH.HCl)∶n(NaOH)=1∶3.30∶7.26,反应温度28℃,催化剂滴加速率1.5mL/m in,肟化反应时间8 h。在该优化条件下,产品中羟肟酸质量分数达到77.6%。该法不经历甲醇酯化,直接肟化,工艺简单,避免使用有毒原料甲醇,对环境友好。将合成产品应用于低品位胶磷矿一步浮选,获得了精矿P2O5品位30.51%,回收率79.16%,尾矿P2O5品位6.89%的良好指标。结果表明,烷基羟肟酸对低品位胶磷矿具有良好的浮选选择性能。

Synthesis of alkyl hydroxamic acids with coconut oil and its application

Alkyl hydroxamic acid was synthesized directly from coconut oil and hydroxylamine hydrochloride by hydroxylamine-coconut oil method under the catalysis of sodium hydroxide.The target product was confirmed to contain alkyl hydroxamic acid through Fe3+ qualitative detection and the analysis of the infrared spectra of coconut oil and the end products.The effects of the molar ratio of feed,reaction temperature,addition rate of NaOH and reaction time on the conversion rate of product were investigated.The results show that the content of product could be reach 77.6% when the mass ratio of feed was n(coconut oil)∶n(NH2OH·HCl)∶n(NaOH)=1∶3.30∶7.26,the reaction temperature was 28 ℃,the addition rate of NaOH was 1.5 mL/min and the reaction time was 8 h.The new process has the advantages of not experiencing esterification with poisonous methanol,direct oximation,simple operation and being environment-friendly.The alkyl hydroxamic acid was applied to low grade phosphate floatation and the good result was obtained that the concentrate grade of P2O5 was 30.51%,the recovery of P2O5 was 79.16%,tailings grade of P2O5 was 6.89%,which shows that the alkyl hydroxamic acid has a good selection performance on the low grade phosphate rock floatation.