曼尼希碱类缓蚀剂缓蚀性能及其影响因素

酸性介质中曼尼希碱缓蚀剂能够较好地抑制碳钢腐蚀,是典型的吸附型缓蚀剂。曼尼希碱型缓蚀剂与金属发生作用生成钝化膜,或者与介质中的离子发生反应生成沉淀膜,从而使金属的腐蚀速率减小。曼尼希碱型缓蚀剂对金属电极发生了阻滞作用,减小阴、阳极腐蚀反应速率。本文分析了曼尼希碱对碳钢的缓蚀作用行为,及与其他缓蚀剂的协同作用机制,初步探讨了缓蚀作用机理和缓蚀影响因素,为进一步探索和研发新型曼尼希碱海水缓蚀剂提供理论参考。     

一种酸化曼尼希碱季铵盐缓蚀剂的合成及性能研究

以丙烯酸羟乙酯、乙酰氯、甲醛、二乙醇胺为主要原料,通过Mannich反应合成曼尼希碱,曼尼希碱再与氯化苄反应进行季铵化,得到曼尼希碱季铵盐缓蚀剂。通过红外光谱对产物结构进行了表征;采用静态挂片失重法、电化学方法和电镜扫描法考察了该缓蚀剂的缓蚀性能。结果表明:该缓蚀剂是以抑制阳极为主的混合型吸附成膜缓蚀剂;在缓蚀剂质量分数为0.9%,腐蚀介质盐酸质量分数为20%,腐蚀温度为90℃,腐蚀时间为12 h及常压条件下,对N80钢的缓蚀率达到96.2%,能有效抑制盐酸对N80钢的腐蚀。     

曼尼希碱酸化缓蚀剂的缓蚀性能评价

以水为溶剂,苯乙酮、甲醛、二乙胺为原料,苄基三乙基氯化铵为相转移催化剂经醛酮胺缩合得到曼尼希碱酸化缓蚀剂。采用挂片失重法、交流阻抗法考察了该曼尼希碱在酸性腐蚀环境下的缓蚀性能。结果表明,该曼尼希碱缓蚀剂是以抑制阳极过程为主的混合型缓蚀剂。缓蚀率随曼尼希碱加入量的增加而增大,当缓蚀剂的加入量体积分数为0.7%时,缓蚀率高达98.5%;随着腐蚀环境温度的升高,缓蚀率有所下降,但在90℃时仍具有较高的缓蚀率;能够有效抑制盐酸对20#碳钢的腐蚀。     

曼尼希碱酸化缓蚀剂的缓蚀性能评价

以水为溶剂,苯乙酮、甲醛、二乙胺为原料,苄基三乙基氯化铵为相转移催化剂经醛酮胺缩合得到曼尼希碱酸化缓蚀剂。采用挂片失重法、交流阻抗法考察了该曼尼希碱在酸性腐蚀环境下的缓蚀性能。结果表明,该曼尼希碱缓蚀剂是以抑制阳极过程为主的混合型缓蚀剂。缓蚀率随曼尼希碱加入量的增加而增大,当缓蚀剂的加入量体积分数为0.7%时,缓蚀率高达98.5%;随着腐蚀环境温度的升高,缓蚀率有所下降,但在90℃时仍具有较高的缓蚀率;能够有效抑制盐酸对20#碳钢的腐蚀。     

曼尼希碱缓蚀剂缓蚀机理及影响因素分析

采用曼尼希碱缓蚀剂增加了电化学阻抗谱等效电路中的膜电阻和电荷转移电阻。曼尼希碱季铵盐缓蚀剂不仅降低了腐蚀反应动力学方程中的指前因子,而且增加了腐蚀反应的活化能,从而减缓了腐蚀速率。分析曼尼希碱缓蚀剂缓蚀机理及其缓蚀效果影响因素。     

氯化钠对曼尼希碱型盐酸缓蚀剂缓蚀性能的影响

研究一种曼尼希碱盐酸缓蚀剂,在不同氯化钠含量的工业盐酸介质、不同温度、盐酸浓度以及缓蚀剂加量的条件下,通过失重法和电化学法测试了上述条件对曼尼希碱盐酸缓蚀剂缓蚀性能的影响,并对曼尼希碱盐酸缓蚀剂缓蚀机理和产生影响的原因进行了初步探讨。研究表明,盐酸介质中氯化钠含量对曼尼希碱盐酸缓蚀剂有一定影响,且随着氯化钠含量的增加,钢片的腐蚀速率升高。海上油田酸化施工海水配制酸液时,应考虑氯化钠对曼尼希碱盐酸缓蚀剂的影响。井下温度以及酸液浓度同样会影响缓蚀剂的缓蚀性能,可适当增加缓蚀剂的加量以达到降低腐蚀速率的效果。     

EDTA-锑与曼尼希碱的缓蚀协同作用

在一定质量分数的工业盐酸中,测试了曼尼希碱与EDTA-锑配合物(SbY)组成的复合缓蚀剂对J55钢腐蚀速率、动电位扫描极化曲线和交流阻抗谱,推测了曼尼希碱与SbY组成的复合缓蚀剂的作用机理。结果表明,随着SbY在复合缓蚀剂中加量的增大,J55钢片的腐蚀速率呈现出先减小后增大的变化趋势,曼尼希碱与SbY在一定的配比下具有良好的协同缓蚀作用。温度为90℃时,在质量分数为15%工业盐酸中,当SbY加量为曼尼希碱加量的0.5%,复合缓蚀剂加量为酸液质量的1.0%时,J55钢的腐蚀速率为0.987 g/(m2.h);在质量分数为20%工业盐酸中,当SbY加量为曼尼希碱加量的1.0%,复合缓蚀剂加量为酸液质量的1.0%时,J55钢的腐蚀速率为2.910 g/(m2.h)。电化学测试结果显示,曼尼希碱与SbY组成的复合缓蚀剂是以阴极控制为主的混合型缓蚀剂。     

一种苯并咪唑衍生物对盐酸中N80钢的缓蚀作用

采用失重法研究了1-苯胺甲基苯并咪唑(PB)在5 M盐酸介质中对N80钢的缓蚀行为。结果表明,PB缓蚀剂对盐酸介质中的N80钢有明显的缓蚀作用;缓蚀剂PB的加入,提高了腐蚀反应的活化能,抑制了腐蚀作用的发生。     

咪唑啉曼尼希碱缓蚀剂对碳钢的缓蚀性能研究

利用动态失重法、电化学测试技术以及SEM-EDS测试方法,研究了在含1 mol/L HCl溶液中分别添加不同浓度的IMDD和IMDDM对10#钢的缓蚀行为的影响。结果表明,60℃动态下1 mol/L HCl溶液的腐蚀介质对10#钢造成严重的局部腐蚀及均匀腐蚀;两种缓蚀剂均属于混合型缓蚀剂,添加缓蚀剂后有效地抑制了10#钢的腐蚀,IMDDM的缓蚀效果高于IMDD。两者均在金属表面发生致密的化学吸附并遵循Langmuir等温吸附方程。     

醛酮胺缩合物的合成及缓蚀性能研究

以酮类、甲醛和有机胺为原料合成了曼尼希碱,用失重法评价了产物在质量分数为15%或20%盐酸中对N 80钢片的缓蚀性能。合成的优化缓蚀剂DS 17在介质温度为40～80℃,腐蚀时间4h,缓蚀剂加量0.8%的腐蚀试验中,腐蚀速度小于5.0g/m2·h。其缓蚀作用的过程可能是曼尼希碱与铁原子(离子)络合吸附成膜,通过覆盖效应起到缓蚀作用。     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

典型煤碳燃烧特性研究和数值模拟

本文以三种典型煤的碳燃烧为研究对象，分别采用简单一维沉降燃烧方式和等温加热燃烧方式，实验研究了煤在快速加热条件下，其碳的初期和中，后期燃烧过程。以实验为基础，建立了煤的碳燃烧模型，变工况数值模拟了煤的碳燃烧过程，揭示了煤不同条件下的单颗粒碳燃烧特性。     

用两个形状指数表征粉煤灰颗粒形貌的研究

引用两个形状指数表征颗粒形状的概念,即先将颗粒形状近似为椭圆,再将椭圆图像分离:以圆为基准的颗粒宏观形状指数δ;以光滑椭圆为基准的颗粒轮廓凹凸度,即微观形状指数ζ。分析和发展了近似椭圆模型。并运用图像分析仪对粉煤灰、水泥样品进行实验。结果表明,粉煤灰颗粒的两个形状指数δ和ζ都大于水泥颗粒。证明粉煤灰颗粒的球形度、表面光滑度优于水泥,而且,随着粒径增大,δ和ζ呈下降趋势,表明磨制颗粒越粗。(?)粒形状越不规则。文中还运用近似椭圆模型再现了颗粒的模拟图像。