Synthesis and structural characterization of regio-controlled oligomers from 2-naphthalensulfonic acid and formaldehyde

A Study on Modified Methylnaphthalene Sulfonate Formaldehyde Condensates: Synthesis, Structures and Asphalt Emulsification

The novel surfactants of sulfonated methylnaphthalene-formaldehyde condensates modified with poly (ethyleneglycol) monooctylphenyl ether (OP-10), 4-octylphenol or octadecylamine were synthesized as anionic emulsifier for the preparation of asphalt emulsions and cement mortar. The experimental results revealed that the modified methylnaphthalene sulfonate formaldehyde condensates (MSFC-OP10, MSFC-OCP and MSFC-OAM) containing a substantial amount of hydrophobic and lipophilic groups in the main chain would exhibit a superior effect both in dispersability and emulsifying property. When cement is mixed with the emulsified asphalt containing MSFC-OP10, MSFC-OCP or MSFC-OAM, the free as-synthesized condensates in the emulsified asphalt exhibited a fairly good dispersing performance and this emulsified asphalt appeared to be relatively stable as well. The presence of either MSFC-OP10, MSFC-OCP or MSFC-OAM in the asphalt emulsion would not only markedly improve its stability, delay its demulsification process, but also would upgrade and restrain both the settlement and stratification of the mixed mastics.

Method development for trace determination of poly(naphthalenesulfonate)-type pollutants in water by liquid chromatography-electrospray mass spectrometry

A very sensitive analytical procedure based on LC-MS for determining trace amounts of the more relevant poly(naphthalenesulfonate) (PNS) contaminants present in environmental waters is presented. Extraction was performed on a styrene-divinylbenzene copolymer resin solid-phase extraction cartridge after addition of ammonium acetate to the sample. Small amounts of ammonium acetate in the mobile phase allowed the determination and characterisation of the four shorter oligomers by liquid chromatography-electrospray mass spectrometry. Under such conditions the electrospray process generates fully ionised molecules which greatly simplifies interpretation of spectra and quantitation. Additionally, confirmatory ions can be generated by the in-source collision-induced decomposition process. The effectiveness of the method was assessed in recovery experiments from drinking and river water samples spiked with commercial mixtures of PNS concrete plasticizers also referred as naphthalenesulfonate-formaldehyde condensates. Moreover, the performance of this method was compared to methods using ion-pair chromatography coupled with fluorimetric and mass spectrometric detection. Method detection limits were in the low picomolar range (1 ng/l for the monomer) for each isomer. In order to evaluate the environmental relevance of PNS type compounds waste, river and ground water grab samples were analysed. Concentrations of PNS oligomers detected in these samples ranged between 53 ng/l and 32 microg/l.

Improved measurement of formaldehyde in water-soluble polymers by high-performance liquid chromatography coupled with post-column reaction detection

An improved methodology for the analysis of free formaldehyde in water-soluble polymers used for industrial water treatment is reported. Previously, derivatization prior to HPLC or colorimetric techniques has been used. The data generated by these approaches are suspect in that the derivatizing agent can react with the polymer or other sample components to produce high results. Post-column reaction derivatization is applied after separation of the free formaldehyde from the product interferences. The type of polymer product analyzed influences the choice of column(s). The degree of high bias of the commonly used 2,4-dinitrophenylhydrazine pre-column derivatization is reported and the results are compared to those with the post-column reaction for two polymer products. This method, being more selective, should be applicable to any polymer containing formaldehyde.