Acrylic acid formation

A kinetic study carried out with a well-stirred reactor was reported by Cartlidge et al. [78,79], Temperatures below 420°C were used to avoid acrylic acid formation. At atmospheric pressure, the oxygen and propene concentrations were varied between 1 and 10, and 5 and 15%, respectively. Selectivities of 60—90% and a maximum acrolein yield of 28% were reported at 400° C. The kinetic results were fitted to a Langmuir—Hinshel-wood type of rate equation... 

An example of real bifunctionality appears to be the case of acrylic acid formation, because two reaction steps which can be individually studied, are involved, i.e. the formation of acrolein, in which lattice oxygen is incorporated, and the aldehyde to acid conversion, which involves water as the oxygen source. The most effective catalysts are multi-component catalysts, which very likely possess different sites, probably on different catalyst phases (see Sect. 2.3.3). 

Acrylic acid formation barely detected barely detected... 

Acrylamide with a demand of 200,000 tons year" is one of the most important commodities in the world. It is used for the preparation of coagulators, soil conditioners, stock additives for paper treatment, and in leather and textile industry as a component of synthetic fibers. Conventional chemical synthesis involving hydration of acrylonitrile with the use of copper salts as a catalyst has some disadvantages rate of acrylic acid formation higher than acrylamide, by-products formation and polymerization, and high-energy inputs. To overcome these limits since 1985, the Japanese company Nitto Chemical Industry developed a biocatalyzed process to synthesize... 

Acrylic acid formation, 61 Activation catalysis, 28 Activation energies, 112 Activation energy barrier electronic rearrangements, 99 Michaelis complex formation, 95 reduction of ruthenium, 173 Activation of CO, 131/ Activation parameters, 31... 

The rate of acrylamide formation is lower than that of acrylic acid formation. 

R2 represents the cell growth (biomass formation) from glucose with inhibition by lactate. The biomass formed is converted into active cellular material. The reaction rates (i 3) and R4) describe the lactate and acrylic acid formation, respectively. 

It must also be indicated that the presence of water in the reaction gas mixture is essential to obtain high acrylic acid yields over these mixed-metal oxide catalysts. An IR spectra of propylene on these catalysts suggest that jt-allyl intermediate (key for the acrylic acid formation) is not formed in the absence of water, while it is clearly observed when both propylene and water are present ... 

Sanseverino, J., Montenecourl, B.S., Sands, J A., 1989. Detection of acrylic acid formation in Megasphaem elsdenii in the presence of 3-butynoic add. Applied Microbiology and Biotechnology 30,239-242. 

Dimer formation, which is favored by increasing temperature, generally does not reduce the quaHty of acryhc acid for most applications. The term dimer includes higher oligomers formed by further addition reactions and present in low concentrations relative to the amount of dimer (3-acryloxypropionic acid). Glacial acrylic acid should be stored at 16—29°C to maintain high quaHty. 

Minimize stocks and segregate from other chemicals and work areas. Where appropriate, keep samples dilute or damp and avoid formation of large crystals when practicable. Add stabilizers if possible, e.g. to vinyl monomers. Store in specially-designed, well-labelled containers in No Smoking areas, preferably in several small containers rather than one large container. Where relevant, store in dark and under chilled conditions, except where this causes pure material to separate from stabilizer (e.g. acrylic acid). 

The addition of comonomers during the polymerization enables a higher flexibility compared to PVAc-homopolymerizates. This results in a lower glass transition temperature and a lower minimum temperature of the film formation. Possible comonomers are acrylic acid esters (butylacrylate, 2-ethylhexylacrylate), dialkylfumarates, ethylene and others. 

The Diels-Alder reaction of a diene with a substituted olefinic dienophile, e.g. 2, 4, 8, or 12, can go through two geometrically different transition states. With a diene that bears a substituent as a stereochemical marker (any substituent other than hydrogen deuterium will suffice ) at C-1 (e.g. 11a) or substituents at C-1 and C-4 (e.g. 5, 6, 7), the two different transition states lead to diastereomeric products, which differ in the relative configuration at the stereogenic centers connected by the newly formed cr-bonds. The respective transition state as well as the resulting product is termed with the prefix endo or exo. For example, when cyclopentadiene 5 is treated with acrylic acid 15, the cw fo-product 16 and the exo-product 17 can be formed. Formation of the cw fo-product 16 is kinetically favored by secondary orbital interactions (endo rule or Alder rule) Under kinetically controlled conditions it is the major product, and the thermodynamically more stable cxo-product 17 is formed in minor amounts only. 

We have studied the effect of monomer concentration in the dispersion polymerization of styrene carried out in alcohol-water mixtures as the dispersion media. We used AIBN and poly(acrylic acid) as the initiator and the stabilizer, respectively, and we tried isopropanol, 1-butanol, and 2-butanol as the alcohols [89]. The largest average particle size values were obtained with the highest monomer-dispersion medium volumetric ratios in 1-butanol-water medium having the alcohol-water volumetric ratio of 90 10. The SEM micrographs of these particles are given in Fig. 15. As seen here, a certain size distribution by the formation of small particles, possibly with a secondary nucleation, was observed in the poly-... 

Blends based on polyolefins have been compatibilized by reactive extrusion where functionalized polyolefins are used to form copolymers that bridge the phases. Maleic anhydride modified polyolefins and acrylic acid modified polyolefins are the commonly used modified polymers used as the compatibilizer in polyolefin-polyamide systems. The chemical reaction involved in the formation of block copolymers by the reaction of the amine end group on nylon and anhydride groups or carboxylic groups on modified polyolefins is shown in Scheme 1. 

In distinction to other esters of acrylic acids containing double bonds in the alcohol radical and, therefore exhibiting a tendency to cyclopolymerization43 and formation of crosslinked polymers, 10 reacts with AN in DMF solution41 or in benzene/DMF42 only with the vinyl group of the acid part due to deactivation of the double bond in the 3-chloro-2-butenyl group by the chlorine atom. The copolymer of structure 11 is formed. 

The precipitation of CaCOj in the presence of a Na-salt of poly(acrylic acid) (PAA) (Mn=5100) was also carried out under the same condition described above. In the presence of the Na-salt of poly(acrylic acid) (PAA), the formation... 

The two procedures give rise to different results. In both cases acrylic acid, present in the form of acrylate, readily reacts with ammonia at r.t. forming a species characterized by an intense band at 1535 cm i indicating the formation of an amide. With increasing reaction temperature (100°C), however, in the case of procedure A the band at 1535 cm shifts to 1495 cm-i and a weak band forms at 1720 cm h The latter band is characteristic of undissociated and weakly coordinated acrylic acid. This indicates that at 100°C amide dissociates with formation of the free acid. When ammonia is instead present in the gas phase (procedure B), the amide species undergoes transformation to acrylonitrile with a maximum in the intensity Fig. 6 IR spectra of 1 torr acrylic of the vcn band at 2220 cm- at an evacuation acid in contact (5 min) with Sb V=l temperature of about 300°C. and evacuation at r.t (a), and fol- Coordinated acrylic acid and ammonia thus lowing evacuations at 100 (b) and react faster at r.t. to form acrylamide, but in 200°C (c). absence of ammonia which inhibits the re-... 

This concept covers most situations in the theory of AB cements. Cements based on aqueous solutions of phosphoric acid and poly(acrylic acid), and non-aqueous cements based on eugenol, alike fall within this definition. However, the theory does not, unfortunately, recognize salt formation as a criterion of an acid-base reaction, and the matrices of AB cements are conveniently described as salts. It is also uncertain whether it covers the metal oxide/metal halide or sulphate cements. Bare cations are not recognized as acids in the Bronsted-Lowry theory, but hydrated... 

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