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The purpose of this paper is to set out a study of a Mannich base, which was synthesized and used as an acidizing corrosion inhibitor first, and to the corrosion inhibitor mechanism.

A Mannich base, 1-phenyl-3-(1-pyrrolidinyl)-propanone (PHPP), was synthesized with acetophenone, pyrrolidine and formaldehyde at pH = approximately 2-3. The structure of PHPP was characterized by elemental analysis and Fourier transform infrared spectroscopy (FTIR). The corrosion inhibition of PHPP on N80 steel in 15 per cent hydrochloric acid (HCl) was studied by weight loss method, scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDAX), and the adsorption behavior of PHPP on the surface of N80 steel was discussed.

The results showed that the inhibition efficiency reached to 99.8 per cent and corrosion rate was 2.65 g·m-2·h-1 at 0.6 per cent of PHPP concentration in 15 per cent HCl, which indicated that PHPP presented excellent corrosion inhibition performance. The results of SEM and EDAX analysis showed that PHPP could be absorbed on the surface of N80 steel. The adsorption process of PHPP on the surface of N80 steel was chemisorption. This process was spontaneous and obeyed Langmuir adsorption isotherm.

It was found that PHPP presented excellent corrosion inhibition performance, and it is practicable to enhance oil production in oilfield development as a oil-well acidizing inhibitor. The study results can provide theoretical guidelines for the development of the inhibitor.

In this work, a kind of Mannich base (C₂₁H₂₅NO) was synthesized with cinnamal aldehyde, acetophenone and diethylamine in a condensing reflux device based on the conventional method. Optimization of the inhibitor concentration was explored.

Spectral properties of this compound was investigated by FTIR, and its inhibition efficiency and mechanism on N80 steel in 20% hydrochloric acid solution were studied by weight loss measurement, electrochemical measurement (potentiodynamic polarization and electrochemical impedance spectroscopy) and surface analytical measurement (scanning electron microscope with energy dispersive spectrometer).

The results showed that the new inhibitor reduced the double-layer capacitance and increased the charge transfer resistance. The inhibition efficiency is 99.7% when the concentration of C21H25NO is 3%. The adsorption of C₂₁H₂₅NO on N80 steel surface in 20% HCl solution was found to be spontaneous and steady. Observed from the steel surface, an inhibition film was confirmed to be presented after adding inhibitor and successfully hindered the corrosive ions from reaching the bulk steel.

A new Mannich base (C₂₁H₂₅NO) was synthesized by cinnamal aldehyde, acetophenone and diethylamine for the corrosion prevention of N80 steel in 20% hydrochloric acid solution.

A novel compound was synthesized by cyclohexylamine, acetophenone and cinnamaldehyde through Mannich reaction in laboratory to use as corrosion inhibitor for steel in acidification process.

The corrosion and inhibition of 13Cr stainless steel in conventional acidification solution were investigated by electrochemical measurements and soaking experiments. The corrosion appearance was observed with scanning electron microscope on the whole surface of 13Cr stainless steel in 20% HCl solution, and the protection film was confirmed on the surface in presence with inhibitor.

Results manifested that the inhibitor C23H27NO can effectively inhibit the corrosion reaction by forming an adsorption layer function as a barrier. Polarization curves indicated that the mixed inhibitor can reduce anodic dissolution and cathodic hydrogen evolution reactions simultaneously. The results of impedance measurements indicated that this inhibitor cannot change the corrosion mechanism of 13Cr stainless steel in 20% HCl solution. The results of the study can provide a theoretical basis for the application of 13Cr stainless steel in conventional acidification solutions during oil well acidification construction process.

A novel compound was synthesized by cyclohexylamine, acetophenone and cinnamaldehyde through Mannich reaction in laboratory to use as corrosion inhibitor for steel in acidification process. The corrosion and anti-corrosion mechanism of 13Cr steel in acid solution was proposed.

Epoxy curing agents are used to cure epoxy resins by reacting with the epoxide groups or by promoting self‐polymerisation of the epoxy by catalytic action. Application characteristics and final physical properties can be tailored by the choice of curing agent. The purpose of this study was to reduce the cost of epoxy hardeners (polyamide and Mannich base, which are commercially available) without affecting the properties of epoxy system and which are also useable as low temperature curing in flooring.

To prepare cost effecting Mannich base curatives for low temperature working environment without significantly affecting the properties such as toughening, adhesion, chemical resistance, etc. various compositions were made by incorporating liquid epoxy resin.

Mannich base curatives were prepared by using different amounts of phenol/bisphenol‐A, formaldehyde and polyamines to obtain products having different amine value, viscosity and colour. Liquid epoxy resin was cured by these Mannich base hardeners prepared. Drying time of relevant thin films was observed. These curatives showed excellent curing property at low temperature as well high humid conditions.

Mannich base curatives, used in present work was synthesised from phenol, DETA and dimethylamino propylamine. Besides, it could be synthesised from other phenol derivative such as cresol, resorcinol and cardanol. In the same manner, we can use other polyamines such as ethylenediamine.

The method provided a simple and practical solution to reducing the cost of Mannich base hardener without significantly affecting the desired properties.

The method used to prepare Mannich‐based hardener was cost affective and could find numerous applications in protective coatings.

Introduction Most corrosion protection systems used for maintenance, as well as binders for the building and civil engineering industries, are cold‐curing formulations. Elevated temperature cure is usually excluded by the size and shape of the substrate to be coated. Consequently, the selection of binders that are suitable for these surface protection systems is limited to those that combine the following properties:

Cyclohexanone–formaldehyde resin (CFR) was in situ modified with isocyanuric acid (ICA) in the presence of hydrochloric acid or p-toluenesulfonic acid by condensation polymerization. The purpose of this study is to produce isocyanuric acid-modified ketonic resins that have higher melting and decomposition temperature, and to use the produced resin in the production of fire-retardant polyurethane.

Two methods were used for in situ preparation of ICA-modified CFR in the presence of an acid catalyst. Method I: cyclohexanone, paraformaldehyde and ICA were mixed, and then an acid catalyst was added to form the modified CFR. Method II: ICA and formalin were mixed to produce N, N, N-trihydroxymethyl isocyanurate, and then water was removed under vacuum. The produced N, N, N-trihydroxymethyl isocyanurate solution was mixed with cyclohexanone and paraformaldehyde, then an acid catalyst was slowly added to this mixture to obtain ICA-modified CFR.

CFR was prepared in the presence of an acid catalyst. The product, CFR, has a dark red colour. The resulting resins have similar physical properties with the resin prepared in the presence of a basic catalyst. The solubility of ICA-modified CFR is much different than CFR in organic solvents.

This study focuses on obtaining an ICA-modified ketonic resin. Cyanuric acid has the form of an enolic structure under a basic condition; therefore, it cannot give a product with formaldehyde under basic conditions. The modification experiments were carried out in acidic conditions.

This study provides technical information for in situ modification of ketonic resin in the presence of acid catalysts. The resins may also promote the adhesive strength of the coating and provide corrosion inhibition on metal surfaces for a coating. The modified resins may also be used in the field of fire-retardant polyurethane applications.

These resins may be used for the preparation of non-toxic fire-retardant polyurethane foam. Polyurethane containing ICA-modified resin may exhibit better fire-retardant performance because of the incorporation of ICA molecule into the polyurethane structure.

ICA-modified CFRs have been synthesized in the presence of an acid catalyst, and the ICA-modified resin was used to produce fire-retardant polyurethane.

Developments in the area of epoxy resins make rich contributions to the patent literature. The single subject on which more patents are issued than any other is curing agents. Accordingly, this section will describe some of the patents on epoxy resin curing agents that have been issued in the past few years. Associated with the curing agents are catalysts, coreactants, and modifiers.

The Fourth four yearly CEC International Symposium on the performance evaluation of automotive fuels and lubricants was held at the Birmingham International Conference Centre on 5 to 7 May 1993. Among the 350 delegates from the 11 CEC national organizations in Europe were representatives from Croatia, India, South Africa, Japan, Canada and the USA. No one turned up to present the paper from the All‐Russian Scientific Research Institute of Oil Refining.

The degradation of coatings is, of course, a major area of interest for paint chemists. One of the coatings that degrades, much to the consumer's despair, is automotive coatings. The degradation of an acrylic‐melamine, cross‐linked coating containing finely dispersed pigment, metallic flake, and other additives was studied by English and Spinelli (Organic Coatings and Applied Polymer Science Proceedings, preprints of papers presented by the Division of Organic Coatings and Plastics Chemistry at the American Chemical Society, 185th National Meeting, Seattle, Washington, March 20–25, 1983, p. 733) using diffuse reflectance infra‐red spectroscopy. They found that the degradation is facilitated near the surface by ultra‐violet light and that there is a cleavage of the nitrogen‐carbon bond on the methoxymethylamino moities. Much of the degradation appears to take place at the surface level and degradation of bonds does not lead to significant self‐condensation of the degraded materials. The authors indicate that they are currently using MMR techniques to identify the products of degradation.

Despite some 30‐plus years of commercial availability and numerous applications, there are continuing new demands set for epoxy resin systems and consequently upon the curing agent component of them. Varied reasons for the development of some new curing agents are described.