Acrylic acid Alumina

Recently, Wilson Combe (1991) have studied the reactivity of magnesium, zinc, calcium and strontium boroaluminate glasses towards poly(acrylic acid) solutions. The controlling factor would seem to be the alumina content of these glasses which serves to moderate the setting rate of the cements. 

In a large number of oxide flotation plants, sodium silicate (Na2Si03) is used as a gangue depressant. In the past two decades, a new line of depressants has been developed and introduced into a number of operating plants. Some of these depressants include (a) a mixture of sodium phosphate and lignin sulphonate (i.e. depressant 3XD), (b) a mixture of a low-molecular-weight acrylic acid and sodium silicate (depressant 2D) and (c) hydrosol based on the reaction of sodium silicate with alumina sulphate (depressant SD). These depressants were extensively examined on copper oxide ores from the Nchanga mine in Zambia. 

The preparation of fluorinated alcohols was carried out in multistep routes according to the reported procedures.1012 The synthesis of acrylic and methacrylic esters as shown in Table 11.1 was carried out in a fluorocarbon solvent such as Freon 113 by the reaction of the respective fluorinated alcohol with acryloyl chloride or methacryloyl chloride and an amine acid acceptor such as triethyla-mine with examples shown in Scheme 1. Other attempts to esterify the fluoroalcohols directly with acrylic acid or acrylic anhydride were not successful.11 Product purification by distillation was not feasible because of the temperature required, but purification by percolation of fluorocarbon solutions through neutral alumina resulted in products of good purity identified by TLC, FTIR, and H-, 13C-, and 19F- FTNMRs. 

Alternatively, acrylic acid can be obtained in a two-step reactor in which glycerol is catalytically dehydrated with an acid catalyst like H3PO4 on a-alumina [67]. The obtained acrolein is then oxidized with a commercially available oxidation catalyst, viz. Mo/V/W/Cu-oxide on a-alumina, yielding up 55% polymerization grade acrylic acid (Scheme 11.8) [68]. 

Gas-phase oxidation of glycerol has been less investigated than liquid-phase oxidation it occurs via a two-step catalyzed reaction involving first the dehydration of glycerol into acrolein, catalyzed by an acid, and then its oxidation. The same reactions can be conducted in two distinct reactors, in which the first step can be carried out with an acid catalyst such as phosphoric acid over alumina [107]. Then acrolein is oxidized to acrylic acid with a conventional alumina-supported Mo/V/Cu/O catalyst. 

Figure 13. Tunneling spectra of propi-olic acid on alumina immediately after infusion and after 2 months aging at room temperature, and compared with the tunneling spectrum of acrylic acid. The close agreement between the lower two tunneling spectra and the bar spectrum of sodium acrylate indicate that the hydrogenation reaction, shown schematically at the bottom of the figure, is ocurring in the junction after completion. Redrawn from (28).

Typical values for AGaacrylic acid) on alumina and —10 to —16 kJ/mol for polyacrylamide on talc.33 Here the adsorption free energy of a polymer molecule is assumed to be the same as the adsorption free energy of a segment. 

Early catalysts for acrolein synthesis were based on cuprous oxide and other heavy metal oxides deposited on inert silica or alumina supports (39). Later, catalysts more selective for the oxidation of propylene to acrolein and acrolein to acrylic acid were prepared from bismuth, cobalt, iron, nickel, tin salts, and molybdic, molybdic phosphoric, and molybdic silicic acids. Preferred second-stage catatysts generally7 are complex oxides containing molybdenum and vanadium. Other components, such as tungsten, copper, tellurium, and arsenic oxides, have been incorporated to increase low temperature activity7 and productivity7 (39,45,46). 

Special considerations poly(acrylic acid) has acid properties therefore it will interact readily with basic fillers such as for example alumina or magnesium hydrox-ide ... 

Malgat, A., Boisvert, J.P., and Daneault, C., Specific influence of univalent cations on ionization of alumina-coated TiO2 particles and on the adsorption of poly(acrylic) acid, J. Colloid Interf. Sci., 269, 320, 2004. 

Kamel (21) at Drexel University has been developing a bone restorative using an alumina- poly(acrylic acid) composite produced by exposing an aqueous mixture of the blend to y radiation of 1 MRad (Figure 8). The porosity and crosslink density of the system were varied over wide ranges by varying monomer concentration and a heat treatment step to form anhydrides. 

A method for coating microchannel walls with layers as thick as 25 pm was developed by Stefanescu et al. [181]. The microreactor was built from FeCrAl (Aluchrom ). The metal surface was first chemically treated in several steps and afterward annealed at 1200 °C for 1 h to trigger the segregation of aluminum and the formation of an alumina layer on the metallic surface. An alumina washcoat was subsequently deposited from a slurry onto the microstructure and characterized by various physical methods. The authors varied the properties such as viscosity, particle size, and pH of the slurry. Acrylic acid, a component used as dispersant and binder, was found to be particularly important for the adhesion of the alumina layer. 

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. 

At this point it is interesting to compare the evolution of propylene adsorption over catalysts with different surface acid characteristics, i.e. a MoVTeNbO catalyst (active and selective in the partial oxidation of propane to acrylic acid), an alumina-supported vanadium oxide (active in the ODH of propane to propylene), or a MoVNbO mixed oxide (active in the oxidative transformation of propane to propylene and acetic acid). The final products observed in each case were related to the characteristics of the adsorbed intermediates (Fig. 24.7) (i) a ir-allylic compound, interacting with a redox site intermediate in the selective oxidation of... 

Since the discovery by Winslow, many ER fluids have been proposed. The majority of these systems contain a small amount of water [54, 55]. This is because water-containing particle-suspension liquids exhibit very large shear stress when an external electric field is applied [56, 57]. Dispersates for water-containing systems use particles that contain an ionically dissociated group (see Table 1). Inoiganic gels such as silica [58, 59] and alumina [60], and crosslinked metallic salts of poly(acrylic acid) [61, 62] also show the ER effect. 

H3PO4 as an external reference. All solvents were dried over neutral alumina in a solvent system under a positive argon pressure. t-Butyl vinyl tosylate 14, [1] t-butyl vinyl bromide 36 [2] and o-tolyl vinyl-1-chloride 18 [3] were prepared from the parent ketone according to known procedures. o-Tolyl vinyl-2-chloride 44 were synthesized by a Hunsdiecker reaction starting from the o-tolyl acrylic acid [4]. Pd[P(o-tol)3l2 was prepared according to known procedures [5]. 

Application of LbL in different fields of nanotechnology has led to the use of various types of porous and rough surfaces for multilayer growth. One significant use has been foimd in the field of separation science, that is, development of filtration membranes by modifying the surface of the porous membrane support to improve separation performance and antifouling properties. Some examples of such porous membrane support materials are polyethersulfone (PES) ultrafiltration membranes, polyacrylonitrile (PAN) ultrafiltration membranes, membrane of PAN with acrylic acid s ments (poly(acrylonitrile-co-acrylic acdd), porous polyacrylonitrile/ polyethylene terephthalate (PAN/PET) substrates, cellulose acetate membranes, porous ceramic supports, and porous alumina supports. The multilayer materials used for such modifications are listed, but not limited to, common polyelearolytes used for LbL applications, such as PSS, PAH, PDADMAC, PAA, and poly(vinyl sulfate) (PVS) copolymers such as poly(4-styrenesulfonic acid-co-maleic acid) quaternary ammonium salts such as cetyl trimethyl ammonium chloride and tetramethyl ammonium chloride as cationic species or nanoparticles such as Ti02. 

Implantation of artificial teeth has received some study. The approach has been to attach a suitable replica of the original tooth to an artificial, porous base. This serves as a root that permits the ingrowth of new living tissue to fix the prosthesis in place. Greenberg and Kamel (6) proposed the use of a porous composite prepared from aluminum oxide particles dispersed in 50 volume % of aqueous poly(acrylic acid). A composite filled with 0.3 microns alumina is said to have a porosity of 38% and compressive strength of 18,000 psi (124 MPa) while a composite filled with 0.05 microns alumina had a porosity of only 15% and a compressive strength of 28,000 psi (192 MPa). 

Attempts to esterify these directly by the use of acrylic acid or acrylic anhydride were not successful. It was found that a convenient, high-yield synthesis could be carried out in fluorocarbon solvent by the reaction of acryloyl chloride and a tertiary amine acid acceptor. Product purification by distillation was generally not satisfactory because of the temperatures required, particularly for the difunctional compounds, but purification by percolation of the fluorocarbon solvent solutions over activated alumina resulted in colorless products of sufficient purity for effective polymerization. 

Metal oxides such as alumina Polyallyls Polybutadiene Polyamino acids Urethanes Acrylic polymers Cellulose Cross-linked dextrans Agarose... 

Acrylic resins, activated carbon, adipic acid, alfalfa, alga powder, alumina, aluminium, ammonium chloride, animal feed, anthracite, asbestos... 

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