Acrylic acid standardized

Brandt [200] has extracted tri(nonylphenyl) phosphite (TNPP) from a styrene-butadiene polymer using iso-octane. Brown [211] has reported US extraction of acrylic acid monomer from polyacrylates. Ultrasonication was also shown to be a fast and efficient extraction method for organophosphate ester flame retardants and plasticisers [212]. Greenpeace [213] has recently reported the concentration of phthalate esters in 72 toys (mostly made in China) using shaking and sonication extraction methods. Extraction and analytical procedures were carefully quality controlled. QC procedures and acceptance criteria were based on USEPA method 606 for the analysis of phthalates in water samples [214]. Extraction efficiency was tested by spiking blank matrix and by standard addition to phthalate-containing samples. For removal of fatty acids from the surface of EVA pellets a lmin ultrasonic bath treatment in isopropanol is sufficient [215]. It has been noticed that the experimental ultrasonic extraction conditions are often ill defined and do not allow independent verification. 

Electrophilic additions to 7t-deficient heterocycles are less common than those to 7t-excessive heterocycles. However, intramolecular electrophilic cyclizations have been used to access the heterocycles of interest in this chapter <1996CHEC-II(7)49>. Recent examples include the preparation of a pyrrolo[2,3-f]pyrazole 165 by acid-catalyzed condensation of 163 and 164 (Equation 37) <1999SC311> and the reaction of 3-(4-pyrazolyl)acrylic acids 166 with excess thionyl chloride in the presence of benzyltriethylammonium chloride (BTEAC) to afford 4-chlorothieno[2,3-f]pyrazole-5-carbonyl chlorides 167 (Equation 38) <2003RJ0893, 2003ZOK942>. In the latter case, the reaction products were readily manipulated to prepare corresponding carboxylic acids, esters, and amides using standard procedures. 

The acid content of the ethylene/acrylic acid copolymer was determined using a potentiometric titration employing standardized sodium hydroxide. 

Current Work and Industrial Applications. Recent efforts have been directed primarily toward refining the original process by using standard o -(acylamino)acrylic acids as substrates. The synthetic efficiency (in-... 

Analysis for Poly(Ethylene Oxide). Another special analytical method takes advantage of the fact that poly (ethylene oxide) forms a water-insoluble association compound with poly (acrylic acid). This reaction can be used in the analysis of the concentration of poly(ethylene oxide) in a dilute aqueous solution. Freshly prepared poly (acrylic acid) is added to a solution of unknown poly(ethylene oxide) concentration. A precipitate forms, and its concentration can be measured turbidimetrically. Using appropriate calibration standards, the precipitate concentration can then be converted to concentration of poly(ethylene oxide). The optimum resin concentration in the unknown sample is 0.2—0.4 ppm. Therefore, it is necessary to dilute more concentrated solutions to this range before analysis (97). Low concentrations of poly(ethylene oxide) in water may also be determined by viscometry (98) or by complexation with KI3 and then titration with Na2S203 (99). 

Peptidyl macromers, in which a vinyl group was introduced at the N-terminus, were synthesized by solid-phase methodology. More specifically, the peptide H-Gly-Gly-Gly-Arg-Gly-Asp-Ser-Pro-OH had acrylic acid coupled to the N-terminus. The peptidyl macromer was cleaved and deprotected by standard methods. Copolymers of styrene with these peptidyl macromers were prepared by radical copolymerization in DMF soln. Cast films were prepared from a CHC13 soln of copolymers. 

Many of these newer materials have become standard polymers for inclusion in the cooling water formulations from most service companies. There are even tetrapolymers available now (for example, acrylic acid, methacrylic acid, ester, acrylamide, or AA/MAA/E/AM). 

A second PMMA latex was prepared, with 3% acrylic acid (Stage II), in an effort to match the surface acid concentration of the standard acrylic latex. The acid location results in Table II show that the surface acid of this latex was indeed close to that of the standard acrylic. The sedimentation curve for this latex is shown in Figure 6 in which an apparent expansion maximum of about 60 A... 

Radiation curable 100% reactive anhydride + propylene oxide addition + acrylic acid 1 day solvent cook and esterification 100-200°C Equal to low energy standard (B) except for added cost of acrylic acid ... 

In 1957 Standard Oil of Ohio (Sohio) discovered bismuth molybdate catalysts capable of producing high yields of acrolein at high propylene conversions (>90%) and at low pressures (12). Over the next 30 years much industrial and academic research and development was devoted to improving these catalysts, which are used in the production processes for acrolein, acrylic acid, and acrylonitrile. All commercial acrolein manufacturing processes known today are based on propylene oxidation and use bismuth molybdate based catalysts. 

The following were either not reduced or were reduced extremely slowly (<0.01 mmol min" ) under the standard conditions acrylic acid, allylamine, allyl chloride, bicyclo[2.2.1 ]hepta-2,5-diene, cyclohexa-1,4-diene, maleic anhydride and tetrachloroethylene. 

If a manual injection is performed, it may be useful to introduce an internal standard into the sample. For analysis using Aminex, formic acid can be used this compound exits in the chromatogram between lactic acid and acetic acid. Using a C18 column, either maleic acid or acrylic acid... 

Purified mercaptoacetic acid is sold in anhydrous or 85% aqueous forms, most often for subsequent conversion to the esters or to the ammonium, sodium, potassium, or calcium salts. 3-Mercaptopropionic acid is produced from metal hydro sulfides and either acrylic acid or acrylonitrile. Mercaptoethyl tallate is another mercapto-ester used in commercial organotin stabilizers. It is manufactured by a standard esterification of mercaptoethanol and tall oil, a mixture of fatty acids. 

Poly(methacrylic acid), PMA, and poly(acrylic acid), PAA, used in this study were obtained from Polyscience and Aldrich Chemicals Inc., respectively. The molecular weight of PMA measured by standard viscosity methods was 1.1 x 10. The molecular weight of PAA was given as 2.5 x 10 by the Aldrich Chemical Inc. PMA samples of different molecular weight (3.9 x 10, 1.6 x 10 and 6.4 X 10 ) used for studying effects of molecular weight, were synthesized by using different amounts of AIBN and monomer. Free... 

FIG. 9 Dark-field scanning transmission electron microscopy image of an unstained cytochrome b6f complexed with the amphiphilic short poly anions A8-75 (a C8 modified poly(acrylic acid) of 8000). Dark bar tobacco mosaic virus added as an internal standard of diameter 18 nm. Dots complexes of diameter ca. 10-15 nm. Reprinted from Ref. 71. Copyright 1998 with permission from Elsevier.)... 

The catalyst systems employed are based on molybdenum and phosphorus. They also contain Various additives (oxides of bismuth, antimony, thorium, chromium, copper, zirconium, etc.) and occur in the form of complex phosphomolybdates, or preferably heteropolyacids deposited on an inert support (silicon carbide, a-alumina, diatomaceous earths, titanium dioxide, etc.). This makes them quite different from the catalysts used to produce acrylic acid, which do not offer sufficient activity in this case. With residence times of 2 to 5 s, once-through conversion is better than 90 to 95 per cent, and the molar yield of methacrylic acid is up to 85 to 90 per cent The main by-products formed are acetic add, acetone, acrylic add, CO, C02, etc. The major developments in this area were conducted by Asahi Glass, Daicel, Japan Catalytic Chemical, Japanese Gem, Mitsubishi Rayon, Nippon Kayaku, Standard Oil, Sumitomo Chemical, Toyo Soda, Ube, etc. A number of liquid phase processes, operating at about 30°C, in die presence of a catalyst based on silver or cobalt in alkaline medium, have been developed by ARCO (Atlantic Richfield Co,), Asahi, Sumitomo, Union Carbide, etc. 

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