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Polystyrene—Aluminum chloride

Polystyrene-Aluminum chloride." Aluminum chloride forms a water-stable complex with polystyrene-divinylbenzene (1.8%) copolymer denoted as (0 AICI3. In a typical preparation, the copolymer beads (59-100 mesh, 31.0 g.)are treated with carbon disulfide and then anhydrous aluminum chloride (7.5 g.). The mixture is stirred at reflux for 40 min. and then excess AICI3 is destroyed by cautious addition of water. The mixture is stirred until the original orange color fades to light yellow. The (P)-AIClj is filtered, washed with water, then successively with ether, acetone, hot iso-prnpanol, and ether, and finally dried in a vacuum oven for 18 hr. The complex is stable to the atmosphere for over one year. The anhydrous aluminum chloride can be released from the polymer by swelling with various solvents benzene, hexane, carbon disulfide. [Pg.13]

Polystyrene-Aluminum chloride (4, 13 5, 13). ( )—AICI3 catalyzes formation of acetals of benzaldehydes. Some catalysis is observed by the polymer alone, probably because it can entrap the water formed on acetalization. ... [Pg.19]

III. POLYSTYRENE-ALUMINUM CHLORIDE AS A LEWIS ACID CATALYST... [Pg.205]

Among a number of metal chlorides used in organic synthesis, anhydrous aluminum chloride is undoubtedly one of the most effective of Lewis acid catalysts. During the chloromethylation of polystyrene, using aluminum chloride as catalyst, it was observed that all the aluminum chloride could not be removed, even after repeated washing. This was attributed to the formation of a tightly bound polystyrene-aluminum chloride complex. Complex formation was demonstrated by the increase in color (yellow) intensity of the polymer, and by the development of a new characteristic ir band at 1650 cm This complex could act as a mild Lewis acid catalyst for certain organic preparations. [Pg.205]

Solid Superacids. Most large-scale petrochemical and chemical industrial processes ate preferably done, whenever possible, over soHd catalysts. SoHd acid systems have been developed with considerably higher acidity than those of acidic oxides. Graphite-intercalated AlCl is an effective sohd Friedel-Crafts catalyst but loses catalytic activity because of partial hydrolysis and leaching of the Lewis acid halide from the graphite. Aluminum chloride can also be complexed to sulfonate polystyrene resins but again the stabiUty of the catalyst is limited. [Pg.565]

Table 2 presents the results of tests to measure the calorific power, ash content, and chlorides concentration of some of the materials obtained from the separation process, such as polystyrene, aluminum foil, plastic foam, and other plastics (general, clear, colored, black, and vinyl). Polystyrene and clear plastic have very high calorific power and low levels of chlorides, but polystyrene has very high ash content. Figures 10-17 present the samples of waste components from the separation and composting plant of Cantagalo. [Pg.393]

Anion exchange membranes can be made from the same crosslinked polystyrene membrane base by post-treatment with monochloromethyl ether and aluminum chloride to introduce chloromethyl groups into the benzene ring, followed by formation of quaternary amines with trimethyl amine ... [Pg.402]

H. Nanbu, Y. Sakuma, Y. Ishihara, T. Takesue, and T. Ikemura, Catalytic degradation of polystyrene in the presence of aluminum chloride catalyst, Polym. Degrad. Stab., 19, 61-76 (1987). [Pg.72]

Aluminum chloride and its derivatives are the most familiar Lewis acids and are routinely employed in many Lewis acid-promoted synthetic transformations. The first polymer-supported metal Lewis acids to be studied were polymers attached by weak chemical or physical interactions to a Lewis acid. In the 1970s Neckers and coworkers reported the use of styrene-divinylbenzene copolymer-supported AlCl,- or BF3 as catalyst in condensations, esterifications, and acetalization of alcohols [11,12]. This type of polymer-supported AICI3 (1) is readily prepared by impregnation of a polystyrene resin with AICI3 in a suitable solvent. Subsequent removal of the solvent leaves a tightly bound complex of the resin and AICI3. The hydrophobic nature of polystyrene protects the moisture-sensitive Lewis acid from hydrolysis, and in this form the Lewis acid is considerably less sensitive to deactivation by hydrolysis. This polymer complex could be used as a mild Lewis acid catalyst for condensation of relatively acid-sensitive dicyclopropylcarbinol to an ether (Eq. 1) [13],... [Pg.946]

Preparation of Polymeric Substrates. Crosslinked polystyrene containing carboxyl groups was prepared by the Letsinger method. (27) Diphenylcarbamyl chloride (18.5 g, 80 mmole) in 40 ml nitrobenzene was added over a period of 15 min to a well-stirred mixture of 8.3 g (80 mmole) Bio-Bead SX2 and 15.0 g (0.113 mole) of aluminum chloride in 350 ml of dry nitrobenzene. The dark mixture was then warmed at 80 C for 2.5 hr, cooled and treated with 200 ml of water. The resin was separated and washed in succession with dilute hydrochloric acid, methanol, and ether. For hydrolysis, the carboxamido pol3rmer was heated at 103-138 C for 32 hr with a... [Pg.67]

The preparation of the starting material, poly(vinylacetophenone), may be carried out by a Friedel-Krafts reaction of polystyrene in carbon disulfide with acetyl chloride and aluminum chloride by the method of Kenyon and Waugh [95a]. [Pg.404]

Copper-polymer complexes also retain an important position as regards binding with ethylene. When a solid polymer complex was prepared from polystyrene beads, copper(I) chloride, and aluminum chloride, absorption at room temperature by the polymer complex was rapid, and the equilibrium molar ratio of absorbed ethylene to the admitted copper(I) chloride was 1.40. The amount of ethylene absorbed by 1 g of the polymer complex solid was 89 cm STP) [56]. [Pg.391]

When polystyrene is sulfonated in chlorinated hydrocarbons with a complex of dioxane-SOs, the polymer precipitates from solution at low concentrations. Complexes of ketones with SO3 can also be used to sulfonate polystyrene in halogenated solvents. The ratio of sulfonation is more favorable for poly(vinyl toluene) than it is for polystyrene at the same conditions. Also, sulfur dioxide swells polystyrene. The polymer can be sulfonated in this medium with sulfur trioxide or with chlorosulfonic acid. Polystyrene, sulfonated in CS2 with aluminum chloride catalyst, is water insoluble in a free acid form. ... [Pg.429]

Alkylation of biphenyl with cyclohexene gives dicyclohexylbiphenyl, which can be used as a secondary plasticizer for PVC. " " Synthesis of this plasticizer uses Friedel-Crafts reaction with aluminum chloride employed as a catalyst. The application data shows that weight loss and the retention of mechanical properties (tensile strength, elongation, and modulus) are greatly improved with this plasticizer. " A mixture of di- and tri-alkyl (usually propyl) biphenyls is used as a plastieizer for polystyrene, butadiene rubber, epoxy resin, and polyurethane. " ... [Pg.54]

The synthetic pathways developed to access the target pyridazinone arrays are based on the assembly of the exocyclic a,P-unsaturated framework through either Knoevenagel (chemotype A) or Claisen-Schmidt (chemotypes B and C) condensations (Scheme 1.11) with silica-supported aluminum chloride anployed as a catalyst. In comparison with conventional aluminum chloride, the silica-supported equivalent offers several advantages over the free catalyst (milder acidity, superior shelf Ufe, and the ability to condnct nonaqueous workups) and the polystyrene-supported version (no swelling and ability to carry out reaction in polar solvents). [Pg.12]

As another example for one-step functionalization on polystyrene, the Friedel-Crafts acylation with haloacetyl and -propionyl bromide should be mentioned [68,69] (Fig. 19). The haloacylation is performed in nitrobenzene — which has the swelling power of toluene (see Table 3) — catalyzed by aluminum chloride at room temperature for 20 hours, yielding a capacity of 2.2 mequiv. of reactive sites/g of 2% cross-linked polystyrene [69]. The loading with bromoacetyl moieties of 0.05 mequiv./g found in another experiment [68] should be regarded as the lower limit of functionalization for practical use in the Merrifield synthesis. [Pg.25]

The catalyst can be recovered and reused. The reaction is completed in a few minutes at room temperature. Sonication does not change the regioselectivity, e.g., with toluene. Similarly, alkylation of benzene with cyclohexene in the presence of aluminum chloride on silica undergoes a sonochemical acceleration of ca. 10 times, essentially due to the improved mass transport induced by sonication.162 jhg formylation of polystyrene represents an interesting case of a triphasic system, constituted by the polymer, aluminum chloride, and dichloromethyl methylether. Sonication provides a significant improvement. [Pg.150]

When a phenyl ring on the backbone of polystyrene (represented by the solid sphere) is reacted with benzoyl chloride and aluminum chloride, the product is the benzoyl derivative 167 (this is a Friedel-Crafts acylation see Chapter 21, Section 21.3.3). If reacted with 168, the product is 169 (an acyl addition reaction of an organolithium reagent see Chapter 18, Section 18.4). When the methyl group of the pyridine unit in 169 is treated with phenyllithium to form the (pyridyllCHgLi derivative, reaction with formaldehyde leads to 170. If 170 is linked to iV-benzoyl 2 -0-isobutyladenosine-3 -monophosphate (171), the product is 172, in which the first nucleotide is bound to the polymer via the 3 position. [Pg.1466]

Dipolystyryl aluminum chloride, prepared by stoichiometric reaction of 1 mol of AICI3 and 2 mol of living polystyrene, is used together with titanium halide catalyst to synthesize styrene-ethylene block copolymers (189). [Pg.8210]

Polymers containing 18 have been used successfully as metathesis catalysts. For example, a copolymer of with styrene (31 mol percent was treated with isobutyl aluminum chloride and oxygen in hexane and trans-3-heptane. This gave an active metathesis system at 20°C which produced trans-4-octene, trans-3-hexene, and other products (one identified as 4-ethyl-2-octene). Thus, this polymer species appears to behave similar to polystyrene-bound Ti -cyclopentadienyltricarbonylbenzyltungsten as a metathesis... [Pg.262]

The catalyst has been prepared by treating co(polystyrene-DVB) (1.8% cross-linked, 50-100 mesh) with anhydrous aluminum chloride in carbon disulfide, followed by addition of cold water (Neckers et aL, 1972). The polymeric catalyst is filtered off and washed successively with water, ether, acetone, and hot isopropanol, and finally dried in a vacuum oven. [Pg.205]

Aromatic isocyanates are used to acylate aromatic substratesand polystyrene . Reaction of trialkylstannyl substituted arenes 214 with phenyl isocyanate at 20 °C in the presence of aluminum chloride affords A-substituted amides 215. ... [Pg.116]

Poly(p-lithiostyrene), a highly reactive polymer prepared from iodinated polystyrene and lithium, yielded a copolymer containing 62 mol-% p-mercaptostyrene when sulfur was added 61). Similarly, treatment of styrene-divinylbenzene copolymers with sulfur and aluminum chloride yielded sulfur-containing polymers in which 21 % of the incorporated sulfur is present in the form of mercaptan groups (62). [Pg.82]


See other pages where Polystyrene—Aluminum chloride is mentioned: [Pg.330]    [Pg.198]    [Pg.330]    [Pg.198]    [Pg.146]    [Pg.153]    [Pg.42]    [Pg.215]    [Pg.298]    [Pg.54]    [Pg.2]    [Pg.816]    [Pg.953]    [Pg.47]    [Pg.211]    [Pg.14]    [Pg.391]    [Pg.133]    [Pg.115]    [Pg.109]    [Pg.101]    [Pg.61]    [Pg.5574]    [Pg.501]   
See also in sourсe #XX -- [ Pg.13 ]

See also in sourсe #XX -- [ Pg.19 ]




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Aluminum chloride

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