低磷高效水处理剂研究进展

有机膦酸类缓蚀阻垢剂广泛应用于循环冷却水中。概要评述了低磷高效有机膦水处理剂的研制及应用进展,低磷水处理剂包括有机膦羧酸、含磺酸基的有机膦酸、含醚有机膦酸、含膦羧酸聚合物等类型,并对阻垢剂今后的研究工作提出了几点建议。     

Utility of branched chain carboxylic acids in the manufacture of driers

To be useful in the manufacture of driers, a carboxylic acid must yield lead, cobalt, manganese, calcium and zinc soaps which are soluble in paint vehicles and petroleum hydrocarbon thinners. The drying metal soaps of a number of saturated branched chain carboxylic acids were prepared to determine the relationship of acid structure to metal soap solubility. It was found that with the exception of 4-ethyl-5,5-dimethyl-hexanoic acid those branched chain acids containing at least six carbon atoms in the longest straight chain yielded soluble drying metal soaps and were therefore useful in drier manufacture. soluble “basic” lead soaps, pale-colored manganese soaps and reddish purple cobalt soaps were obtained from acids lacking in alpha branching. Alpha-branched acids yielded insoluble basic lead soaps, dark manganese soaps and dark blueviolet cobalt soaps.     

生物柴油腐蚀性试验研究

根据国标GT/B 5096铜片腐蚀试验法测定生物柴油的腐蚀等级,并对主要腐蚀组分试验。测量生物柴油的硫含量和水溶性酸或碱,再结合酸值,分析造成腐蚀性主要原因。结果表明:生物柴油的硫含量、水溶性酸和酸值因素都会对金属腐蚀有影响,并且生物柴油中的低级脂肪酸是造成金属腐蚀的主要原因。     

Effect of lactic acid on the hydration of portland cement

Effect of lactic acid on the hydration of portland cement has been studied by employing various experimental techniques. Results indicate that lactic acid accelerates the hydration contrary to other α-hydroxy carboxylic acids which act as retarder. Electrical conductivity measurements give an indication that lactic acid forms a salt of calcium lactate during the interaction with calcium hydroxide. Zeta potential measurements give negative test regarding the adsorption of lactic acid portland cement surfaces. SEM photographs show that probably lactic acid accelerates the hydration by increasing the crystalline character of calcium hydroxide, which in turn accelerates the nucleation and growth of the hydration products.     

Corrosion inhibitors for chlorides induced corrosion in reinforced concrete structures

Reinforcements corrosion is the most important cause of premature failure on reinforced concrete structures. Phenomena promoting corrosion are the ingress of chlorides and the reaction of atmospheric CO₂ with cement paste. Aim of this paper is the investigation on the effectiveness of three organic commercial inhibitors in preventing carbon steel chlorides induced corrosion in concrete, since there is not yet a clear knowledge on the real effectiveness of these products. Inhibitors were added to the concrete mixture in dosage suggested by the manufacturers. Chlorides were added in the concrete mixture or penetrated from outside by “ponding” cycles with a 3.5% sodium chloride solution. The effectiveness of the inhibitors has been evaluated by long-term rebar corrosion monitoring in reinforced concrete and by rebar visual inspection after three years tests. Also solution tests were performed in order to verify the effectiveness of inhibition. Results give information about corrosion prevention ability of analysed commercial inhibitors.     

膦酰基羧酸的复配及协同效应研究

在优化工艺条件下合成了环境友好型缓蚀阻垢剂膦酰基羧酸(POCA),采用旋转挂片失重法、静态阻垢法对POCA及其各复合配方的缓蚀阻垢性能、协同效应进行了研究,并探讨了缓蚀机理.结果表明,60%(质量分数,下同)POCA与40% PBTC、40% POCA与60% HEDP复配后,在阻碳酸钙垢方面均有协同效应,阻垢率高达100%;40% POCA、32% PBTC、24% HEDP和4%乙酸锌复配后,具有缓蚀协同效应,缓蚀率达到92.22%,阻碳酸钙垢率为90.42%、阻磷酸钙垢率为97.60%,该复合缓蚀阻垢剂是一种以抑制阳极过程为主的混合型缓蚀剂.     

On the chemical reaction between carboxylic acids and iron,including the special case of naphthenic acid

The reaction between different carboxylic acids and iron was performed by monitoring the amount of iron dissolved in oil through the formation of the iron carboxylate and by the product distribution in the gas phase. It was found that the solubility of the given iron carboxylate strongly influences the concentration of iron dissolved in oil. At temperatures higher than 300 °C, however, the iron carboxylate thermally decomposed and, therefore, the dissolved iron underestimates the acid corrosion potential. On the other hand, the accumulated molar amount of hydrogen gas becomes an alternative way to estimate the carboxylic acid corrosion potential.     

Synthesis and Characterization of Sulfur Containing Dextran- and β-Cyclodextrin Derivatives

Summary Sulfur containing dextran and β-cyclodextrin derivatives were synthesised as alternitive coating materials for gold surfaces. The esterification of the carbohydrates with thiophene carboxylic acids and α-lipoic acid was carried out in DMSO by in situ activation of the acids with N,N’-carbonyldiimidazole. The thiophene carboxylic acids vary in the position of the sulfur atom and the spacer between the thiophene and the carboxylic group. DS values ranging from 0.44 to 2.04 were accessible depending both on the carbohydrate and the acid used. Insoluble derivatives were obtained by the conversion of α-lipoic acid with the carbohydrates. The structure of the derivatives soluble in DMSO and DMF was examined by IR- and NMR spectroscopy. Furthermore, subsequent acylation reveals a useful tool for the determination of the degree of substitution of the thiophene derivatives additionally to elemental analysis.     

Corrosion of hardened cement paste by acetic and nitric acids part II: Formation and chemical composition of the corrosion products layer

Nitric and acetic acids attack cement paste. Layers of corrosion products covering the undamaged cement paste were chemically analyzed as a whole as well as across the layer. Analysis of the corrosion process taking place in nitric acid enabled us to calculate the thickness of the brown colored zone in the layer of corrosion products which contained an increased content of hydrated Fe₂O₃, and thus verify various zone formation theories. After about a year of exposure of the cement paste to solutions of lower concentrations, an additional zone in the apparently uncorroded core was seen to form. This so-called “core layer” contains almost no portlandite and in addition it contains an increased content of SO₃.     

冷却水处理中的水溶性聚合物

本文综述了冷却水处理中水溶性聚合的发展历史中与最新进展，讨论了结构与性能的关系，并重点注意了磷酰基和大分子 结合的含磷聚合物。     

The effect of SCMs on the corrosion of rebar embedded in mortars subjected to an acetic acid attack

Agricultural effluents are transformed under bacteria effect into organic acids which constitute severe chemical and electrochemical attacks for the reinforced concrete of agricultural structures. Among supplementary cementing materials (SCMs), blast-furnace slag (GBFS) and metakaolin (MK) are classified chemically resistant to the aggressiveness of acidic media and especially organic acids. The objective of this research was to evaluate the effect of GBFS and MK on the corrosion performance of reinforced mortars. Here, electrochemical measurements allow determining the time needed to initiate the corrosion. Mortar cylinders were made with three cement types including ordinary Portland cement (OPC), GBFS and MK cements at a fixed water/cementitious material (w/cm) ratio of 0.65. Corrosion of rebars was simulated by subjecting cylinder specimens to cyclic loading with acetic acid solution (pH 4, 0.5 M) and drying. Concrete resistivity and reinforcing steel potentials were measured up to 429 days of age. At the end of the experiment, all specimens were saw cut split open, and visually inspected. It was found that the drop in the linear polarization resistance and corrosion potential curves reflect the time needed to initiate the corrosion. Blending the cement with 20% of MK is beneficial with regard to delaying the onset of the corrosion by a factor of more than two. However, using high percentage of GBFS (80%) decreases the time to initiate the corrosion for specimen subjected to acetic acid attack.     

Acid/base properties of MgO studied by high resolution electron energy loss spectroscopy

The acid/base properties of model MgO surfaces have been studied using various probe molecules with acid strengths ranging from those of carboxylic acids and alcohols to alkenes and alkanes. High-resolution electron energy-loss spectroscopy (HREELS) data show that carboxylic acids, methanol and water dissociate heterolytically on MgO surfaces. Ethylene and ethane, however, are found to adsorb associatively. Thermally generated surface defect sites exhibit stronger basic character and are capable of dissociating ethane. The present studies demonstrate the capabilities of HREELS for the investigation of the chemical properties of insulating materials.     

磷系杂多酸的缓蚀性能研究

通过静态、动态挂片失重法对磷钼、磷钨杂多酸盐的缓蚀性能进行了研究、探讨 ,比较了室温、5 0± 1℃时两类杂多酸盐与单钼酸盐、单钨酸盐在偏腐蚀性水介质中对A3 钢的缓蚀作用。实验结果表明 ,杂多酸盐比其简单含氧酸盐具有较优良的缓蚀作用 ,对碳钢缓蚀率可达 90 %以上 ,是一类具有开发前景的低磷、高效、无毒无公害的缓蚀剂     

烟塔合一机组中水冷却的凝汽器在线化学清洗

介绍了烟塔合一机组且使用中水冷却的凝汽器在线化学清洗,使用的膦羧酸类高效清洗剂是由膦羧酸外加分散剂、缓蚀剂、粘泥剥离剂、浸润剂等清洗助剂复配而成的一种全有机化学清洗剂,具有水溶性好,螯合能力强等特点。该药剂在不停车的情况下,对换热器内的污垢起到很好的去除作用,而且对设备的腐蚀很小,安全可靠。     

Improvement of anticorrosive performance of phosphate-based alkyd paints with suitable additives

The purpose of this investigation was focused on reducing the content of zinc phosphate in anticorrosive paints by means of the incorporation of low quantities of selected soluble corrosion inhibitors. The article describes the anticorrosive behavior of alkyd paints containing reduced levels of zinc phosphate, zinc oxide, and some soluble compounds used as additives (e.g., sodium polyphosphate, sodium phosphate, and sodium benzoate). Anticorrosive solventborne alkyd paints were formulated with a zinc phosphate content of 10% by volume (v/v) with respect to the total pigment concentration. In all cases, the PVC/CPVC (pigment volume concentration/critical pigment volume concentration) ratio was 0.8. Experimental paints, applied on sandblasted SAE 1010 panels, were evaluated by accelerated tests (salt spray cabinet) and electrochemical measurements (electrochemical impedance spectroscopy, EIS). The results show that the additions of small amounts of soluble corrosion inhibitors to low content zinc phosphate paint formulations enhance their performance in a very remarkable way. Perhaps, the most outstanding feature is that the employment of soluble additives allowed the reduction of the zinc phosphate content with concomitant savings.     

Retardation effect of styrene-acrylate copolymer latexes on cement hydration

Interactions between styrene-acrylate latexes and cement are investigated with emphasis of the charge properties of the polymer particles by means of calorimetry, adsorption measurement, and confocal laser scanning microscope. Three latexes with varied surface charges of polymer particles were prepared by respectively using methacrylic acid (MAA), sodium styrene sulfonate (SSS) and methyl poly(ethylene glycol) methacrylate (MPEGMA) as water soluble monomers during synthesis. It is found that the polymer latexes retard cement hydration in two manners, namely the delaying effect represented by a delayed hydration peak and the slowing down effect characterized by a reduced main hydration peak during the acceleration period. The delaying effect is closely related to the concentration of carboxylic groups existing in the latex, while the depression effect of hydration rate is majorly caused by the adsorption of polymer particles on surface of cement grains and proportional to the total charge density of polymer particles.     

萤石浮选捕收剂研究进展

萤石捕收剂可分羧酸类、生物脂类、两性捕收剂 、复合捕收剂、烷基膦酸和烷基硫酸(烷基磺酸)等五类,其中绝大部分属化工厂副产品。羧酸类(油酸或油酸盐)仍然是萤石浮选的主要捕收剂。使用两性捕收剂能改善萤石-方解石分离的选择性,而生物脂类则可有效排除萤石精矿小的二氧化硅。     

粉煤灰水泥高效助磨剂的研究

采用羧酸类物质、醇胺类物质、醇类物质作助磨剂,研究了它们对粉煤灰水泥粉磨效果以及物理性能的影响.实验结果表明:羧酸类物质和醇胺类物质比醇类物质助磨效果明显;羧酸类物质对水泥早、后期强度的提高均有利;醇胺类物质和醇类物质只对水泥后期强度的提高有作用.从助磨效果以及增强效果两方面综合分析,羧酸类物质更适合用做粉煤灰水泥高效助磨剂.     

Separation of Aromatic Carboxylic Acids Using Quaternary Ammonium Salts on Reversed‐Phase HPLC. 1. Separation Behavior of Aromatic Carboxylic Acids

Abstract

In order to develop separation processes and analytical methods for aromatic carboxylic acids for the coal oxidation products, the separation behavior of aromatic carboxylic acids on a reversed‐phase HPLC using eluent containing quaternary ammonium salt has been investigated. The retention mechanism of aromatic carboxylic acids was discussed on the basis of both ion‐pair partition model and ion–exchange model. The retention behavior of aromatic carboxylic acids possessing one (or two) carboxylic acid group(s) followed the ion‐pair partition model, where linear free energy relationship was observed between the capacity factor and the extraction equilibrium constants of benzoic acid and naphthalene carboxylic acid. Besides, the retention behavior followed ion‐exchange model with increasing the number of carboxylic acids, where the capacity factor of benzene polycarboxylic acids is proportional to the association constants between aromatic acids and quaternary ammonium ions calculated on the basis of an electrostatic interaction model.     

CORROSION INHIBITION OF CuNi10Fe ALLOY WITH PHENOLIC ACIDS

The purpose of this study was to investigate the efficiency of two phenolic acids, namely p-hydroxybenzoic acid (HBA) and protocatechuic acid (PCA), as corrosion inhibitors for CuNi10Fe alloy in a 0.5 mol dm^?3 NaCl solution. In these investigations, open circuit potential measurements, potentiodynamic polarization measurements, and the linear polarization method have been used. It was found that both phenolic acids had similar corrosion inhibition effects on the CuNi10Fe alloy dissolution. The inhibition efficiency (IE) increased with increase in inhibitor concentration. The polarization shows that both compounds functioned as cathodic corrosion inhibitors by adsorption on the surface of CuNi10Fe alloy according to the Freundlich adsorption isotherm. The numerical values of free energies of adsorption indicate physical adsorption of the compounds on the electrode surface. DFT-based quantum chemical computations and molecular dynamics (MD) simulations revealed identical electronic and adsorption structures for both HBA and PCA, which could account for the similarities in the experimentally observed inhibiting effects.