分析纯EDTA试剂生产工艺的探讨

EDTA是乙二胺四乙酸的简称,其合成方法很多:G.O柯姆(Curme)等氏将N,N,N,N,——四(二羟—乙基)乙二胺与苛性碱溶液在高温经去氢反应而得。H.C契特伍德(Chitwood)氏以同样原料,但改用接触氧化法制备。F,C培斯渥司(Bers—Worth)以氨基乙酸与乙二胺在碱性溶液中用迴流加热的方法制得。后他又改用乙二胺与甲醛及碱金属氰化物在碱性溶液中反应而得……。以上诸方法之缺点不是产     

EDTA的合成及其应用综述

简述了和对比了氯乙酸法,氰化钠法和氢氰酸法合成EDTA的工艺,详细介绍了EDTA在工业生产和日常生活中的应用,最后对EDTA的今后发展提出几点建议。     

成果转让

乙二胺四乙酸主要原料氯乙酸、乙二胺、纯碱、盐酸主要设备反应釜、离心机、去离子水装置、干燥房主要用途广泛用于电子络合剂、水质处理剂、化学分析、丁苯橡胶助剂、日用化学品及医药中间体     

N,N’-双月桂酰基乙二胺二乙酸钠合成方法的改进

对表面活性剂N,N’-双月桂酰基乙二胺二乙酸钠的合成方法进行了改进。以月桂酸、乙二胺和氯乙酸为原料制得N,N’-双月桂酰基乙二胺二乙酸钠。考察了反应温度、反应时间、原料配比对中间体合成的影响。结果表明,N,N’-双月桂酰基乙二胺(中间体Ⅰ)的最佳合成条件是:n(月桂酰氯)∶n(乙二胺)=3.5∶1,反应温度70℃,反应时间1 h,产率为96.94%;N,N’-双月桂酰基乙二胺二乙酸(中间体Ⅱ)的最佳合成条件是:n(氯乙酸)∶n(中间体Ⅰ)=3∶1,反应温度65℃,反应时间12 h,产物产率为53.38%。产物结构用红外光谱、元素分析等方法进行了表征。     

氰化钠法生产EDTA钠盐先进工艺

与传统工艺(经由EDTA中间体)比较,氰化钠法生产EDTA钠盐先进工艺具有如下优点:由EDTA四钠原液生产二钠盐,减少3道工序,硫酸(100%)和氢氧化钠(100%)单耗分别降低0.350t/t和0.216t/t;由二钠盐生产四钠盐减少一道工序,硫酸和氢氧化钠单耗分别降低0.272t/t和0.173t/t;产品纯度99.3%～99.5%,产率93%～95%(以乙二胺计),达到文献水平。     

一种多功能表面活性剂的合成

以长链烷基替代EDTA分子中的一个乙酸基，使其改性为既具表面活性又有络合金属离子能力的多功能表面活性剂。合成分两步，先以乙二胺、溴代烷为原料，合成了中间体N－长链烷基乙二胺(R-en)，然后R－en和氯乙酸反应生成了N－长链烷基乙二胺三乙酸钠盐（RNa3edta)。用正交实验法探讨了R－en的合成条件为：n(乙二胺）：n（溴代烷）＝（2.5-3.0)：1．0，反应温度为60℃，反应时间为8－10h，其收率均达98％。终产品合成条件为n(R-en):n（氯乙酸）＝1．05：2，反应时间为10h，反应温度为80℃，收率达86％。并通过红外光谱、核磁共振氢谱对终产品结构进行了初步确认。     

从氢氰酸制EDTA

EDTA[乙二胺四乙酸(HO_2CCH_2)_2NCH_2 CH_2N(CH_2CO_2H)_2]及其盐类不仅是实验室里重要的分析试剂,而且是工业界广用的精细化学品。早在五十年代,上海试剂一厂已有产品上市,当初以氰化钠法生产,不久改为一氯醋酸法,因国产一氯醋酸供应方便,操作     

甘氨酸生产工艺对草甘膦市场竞争力的影响

甘氨酸（又名氨基乙酸）,其作为一种重要的精细化工中间体,广泛应用于农药、医药、食品、饲料等领域,特别是自全球性除草剂草甘膦问世以来,甘氨酸在农药行业的应用得到了极大增加。１国内外甘氨酸工业状况甘氨酸的生产路线主要有２种:一是以氯乙酸、氨为原料的氯乙酸氨解法;另一是以甲醛、氰化钠（或丙烯腈装置副产的氢氰酸）为原料的施特雷克法。国内现有的２０多家甘氨酸生产厂几乎无一例外的都采用第１种工艺进行生产,但是此法因为工艺流程复杂、生产成本较高,且产品纯度低,在国外已被淘汰。日、美等发达国家的生产厂则都选用第２种方法,…     

氰乙酸甲酯合成研究

以氯乙酸、甲醇为原料,先制备氯乙酸甲酯,再与氰化钠反应合成氰乙酸甲酯,实验得到酯化反应原料配比（氯乙酸：甲醇）以1：1.5为佳,酯化收率达90.6%,氰化反应在季胺盐催化剂存在下,55℃反应3h氰化收率可达80.2%。     

新型Gemini两性表面活性剂的合成研究

以N,N'-二羟乙基乙二胺、氯乙酸和硬脂酸为主要原料合成了一种新型Gemini两性表面活性剂.分别用单因素法和正交法对中间体和终产物的合成条件进行了探讨.中间体合成:n(N,N'-二羟乙基乙二胺)∶n(氯乙酸钠)=1∶3.0,反应温度15～20℃,反应时间24 h;终产物合成:n(中间体)∶n(硬酯酰氯)=1∶2.5,pH 9.0～10.0,反应温度20℃,反应时间5 h.并对所得产品进行结构分析和性能测试.     

不同电源模式下微弧氧化制备陶瓷膜的性能对比研究

在硅酸钠、钨酸钠、硼酸、偏铝酸钠和乙二胺四乙酸二钠的复合电解液中,分别采用交流电源和脉冲电源,利用微弧氧化方法,在ZL102铸造铝合金上制备了陶瓷膜层。通过扫描电镜（SEM）观察,交流电源模式制备的陶瓷膜层表面孔洞少,比用脉冲电源制备的陶瓷膜形貌好。利用电化学方法分析了陶瓷层的防腐蚀性能,交流电源制备的陶瓷膜层耐腐蚀性能好。     

两种小分子甲醛消除剂的合成

利用尿素分别与乙二胺和丙二胺合成了环乙撑脲和环丙撑脲2种小分子甲醛消除剂,考查了原料的摩尔配比、氢氧化钠的用量和反应温度与产率的关系。这2种消醛剂的合成工艺简单、原料易得、产率较高、尤其是环丙撑脲,其产率可达98%以上。     

EDTA络合溶胶-凝胶法制备纳米复相永磁材料

以钐和铁的硝酸盐为起始物,用EDTA络合溶胶-凝胶法制备SmFeO3/Fe2O3复合纳米永磁性粉体,并对工艺参数进行了优化。用TG-DTA、SEM、XRD等手段对制备过程、热分解机理及粉体的性质进行了研究。结果表明:采用分段升温焙烧方式可以明显改变晶化过程;采用无水乙醇对凝胶洗涤、加入合适的分散剂及采用超声波分散都可以在一定程度上减少团聚的产生;同时硝酸根离子在高温条件下可以加速EDTA凝胶的热分解,仅在350℃就有SmFeO3相生成,但此温度下有Sm2O2CO3相出现,需经600℃焙烧2h才能彻底除去。粉体颗粒呈球形,分散性较好,经谢乐公式计算,平均粒径在30nm左右。与传统固相反应相比,该法制得的组分均一,化学计量比易于控制,焙烧温度较低,是一种制备复合钠米材料的有效方法。     

乙撑双油酸酰胺的合成研究

对常压下以油酸和乙二胺为原料合成乙撑双油酸酰胺的方法进行了研究,考察了原料配比、催化剂种类及用量、反应温度及时间对合成反应的影响。确定了最佳工艺条件：n（油酸）：n（乙二胺）=1：0．52,催化剂为磷酸,m（磷酸）：m（油酸）=0．5％0,反应温度185-190℃,反应时间4～5h。在此条件下,产品的酸值〈7．0mgKOH／g,熔点112-118℃。     

Effect of pH, sulfate and sodium on the EDTA titration of calcium

The ethylenediaminetetraacetic acid (EDTA) titration method limits the measurement of calcium concentration to 50 mg/l in water. However, various acids and salt solutions are used in the investigation of the durability of concrete, and the adaptability of the EDTA titration method to determine the calcium in these solutions must be investigated. Hence, the purpose of this study was to investigate the interfering effects of hydrochloric acid, sulfuric acid, sodium chloride and sodium sulfate on measuring the calcium in the aqueous leaching solutions using the EDTA titration method. The calcium standard solutions were prepared using CaCl₂ with initial pH from −0.8 to 7 and calcium concentration up to 160 mg/l. Sulfuric acid and hydrochloric acid were used to prepare calcium solutions with lower pH. Salt solutions with 3% NaCl and 3% Na₂SO₄ were used to evaluate the interfering effects of salt elements such as sulfate and sodium on the EDTA titration. Results indicated that the EDTA titration method was reliable in measuring the calcium up to 160 mg/l, the maximum concentration investigated in this study, in hydrochloric acid with pH higher than zero and 3% sodium chloride solution. Sulfuric acid with pH higher than zero and 3% sodium sulfate solutions showed 3% to 4% less calcium in the solutions. Acid solutions with pH less than zero showed interference with calcium measurement.     

Impact of conditioning regimens and time on adhesion of a fiber post to root dentin using two resin cements

The aim of this study was to evaluate the influence of irrigation protocols on the bond strength of a glass fiber post bonded to dentin using two resin cements. In 200 root-filled teeth, post space was prepared and divided into five groups (n?=?40) based on the irrigation protocol: group 1 (3% sodium hypochlorite), group 2 (3% sodium hypochlorite – 17% Ethylene diamine tetraacetic acid), group 3 (a mixture of sodium hypochlorite and etidronic acid), group 4 (sodium hypochlorite – QMix), and group 5 (distilled water). Samples were subdivided into two subgroups (n?= 10) and fiber posts were cemented using subgroup A (Self-adhesive dual-cure resin cement; SEA) or B (dual-cure resin cement following an etch-and-rinse protocol, ER). Push-out bond strength was performed after 24 h and four months (n?= 10) and failure modes were categorized. Statistical analysis of data was carried out by appropriate analyses (p < 0.05). The irrigation protocol and the resin cement had a significant impact on push-out bond strength. Subgroup A group showed lower bond strength than B at both time periods when 3% NaOCl–17% EDTA and 1:1 mixture of 6% NaOCl + 18%EA protocols were used. Three percent NaOCl used in combination with 17% EDTA or QMix significantly decreased the push-out bond strength of ER at the end of four months (p < 0.05). In conclusion, dual-cure resin cements bonded with etch-and-rinse protocol showed highest bond strength when a mixture of NaOCl and etidronic acid was used as root canal irrigant. These values were differentially influenced by time.     

半干法制酸工艺

主要介绍了半干法制酸工艺原理及特点。半干法制酸以酸性气为原料,经过干燥、焚烧、转化、吸湿、吸收等工序制酸。用干燥塔来控制焚烧炉中的氢硫比,用吸湿塔来吸收转化气中的水。对φ（S）在6%以上的原料气可以实现二转二吸制酸,即使φ（S）在3%也可实现自热平衡的一转一吸制酸。其特点是气浓高、腐蚀性小、吸湿快,具有投资省、副产蒸汽多、尾排指标好、电耗低、维护量少等。     

Adhesive Properties of Medium-Density Fiberboards Fabricated with Rapeseed Flour-Based Adhesive Resins

This study examined the adhesive properties of adhesives formulated with rapeseed flour (RSF), a by-product of edible oil and bio-diesel manufacture, for medium-density fiberboards (MDFs). The RSF was hydrolyzed by sulfuric acid (AC-RSFH) and sodium hydroxide (AK-RSFH) solutions of 3%, 5%, and 7%. Phenol–formaldehyde (PF) prepolymers were prepared with formaldehyde to phenol molar ratios of 1.5, 1.8, and 2.1 (1.5-, 1.8-, and 2.1-PF). RSF-based adhesives were formulated by cross-linking 35% AC-RSFH, 35% AK-RSFH, and 30% PF prepolymers on a solid weight basis. The mechanical strength and dimensional stability of the MDFs were improved by decreasing the concentration of RSF-hydrolytic agents. The properties of the MDFs bonded with RSFH/1.8-PF resins were superior to those of RSFH/1.5- or 2.1-PF resins. These results suggest that RSF can be used as a raw material for environment-friendly adhesives used in MDF production.     

落叶松树皮化学改性及其对铜离子吸附性能的研究

以落叶松树皮为原料,经甲醛改性、盐酸催化处理后制备生物基吸附材料Ⅰ;经环氧氯丙烷改性、氢氧化钠催化处理后制备生物基吸附材料Ⅱ.通过正交实验法得到最佳改性条件：生物基吸附材料Ⅰ最佳改性条件为树皮粒径60～80目,甲醛20mL,盐酸催化剂的浓度0.5mol/L,改性温度50℃,反应时间2h;生物基吸附材料Ⅱ最佳改性条件为树皮粒径60～80目,环氧氯丙烷30mL,氢氧化钠催化剂的浓度0.7mol/L,改性温度70℃,反应时间2h时.实验结果表明：经过改性得到的生物基吸附材料Ⅰ和Ⅱ对铜离子的吸附量分别增加了65％和69％.     

湿法磷酸制备食品添加剂磷酸氢二钠的反应条件控制研究

湿法磷酸是多杂质的复杂原料,开发湿法磷酸的精加工系列产品符合目前市场的需要,具有重要意义.以湿法磷酸为原料,通过对反应条件和结晶条件的控制,降低或除去原料中所含的氯离子、砷离子、氟离子、重金属离子等杂质,直接制得食品添加剂磷酸氢二钠.