Aluminum with phenols

The most important appHcation of metal alkoxides in reactions of the Friedel-Crafts type is that of aluminum phenoxide as a catalyst in phenol alkylation (205). Phenol is sufficientiy acidic to react with aluminum with the formation of (CgH O)2Al. Aluminum phenoxide, when dissolved in phenol, greatiy increases the acidic strength. It is beheved that, similar to alkoxoacids (206) an aluminum phenoxoacid is formed, which is a strong conjugate acid of the type HAl(OCgH )4. This acid is then the catalyticaHy active species (see Alkoxides, metal). 

Other Compounds. Primary and secondary amines add 1,4- to isoprene (75). For example, dimetbylamine in ben2ene reacts with isoprene in the presence of sodium or potassium to form dimetby1(3-metby1-2-buteny1)amine. Similar results are obtained with diethylamine, pyrroHdine, and piperidine. Under the same conditions, aniline and /V-metbylaniline do not react. Isoprene reacts with phenol in the presence of aluminum phenoxide (76) or concentrated phosphoric acid (77) to give complex products. 

Because direct glycosidation of 4 with phenols is not possible, indirect methods must be used for the preparation of aryl D-glucofuranosidurono-6,3-lactones (29). In addition, aryl 2,5-di-O-acetyl-D-glucofuranosidurono-6,3-lactones (30), obtained35-37 from the reaction of 1,2,5-tri-0-acetyl-D-glucofuranurono-6,3-lactones with phenols, can only be deacetylated by such multi-step procedures as (1) ammonolysis of 30 to afford aryl D-glucofuranosiduronamides (31), followed by amide hydrolysis and lactonization, 35,37 or (2) reduction of 30 with lithium aluminum hydride, and subsequent oxidation of the intermediate aryl D-glucofuranosides38 (32) (see Scheme 1). 

Dichloroaluminum phenoxide, CUAIOQH, (1). This aluminum reagent is prepared by reaction of CH,A1C12 with phenol in CH,C12. 

The concept of using group I metal initiators was applied in order to minimize the toxicity generated by heavy metal residues in the end product PLAs when using metals like aluminum, tin, and lanthanides as initiators. In recent years, dinuclear lithium and macro-aggregates with phenolate ligands have attracted substantial interest, mainly due to uncommon strucmral feamres and their ability to catalyze formation of polyester and various other polymeric materials via ROP [28]. A series of lithium complexes supported with 2, 2-ethylidene-bis (4, 6-di-tert-butylphenol) (EDBP-H2) 2-6, (Scheme 6) are excellent initiators for the ROP of L-lactide in CH2CI2 at 0 °C and 25 °C [33-35]. In this case, the PDIs of the obtained PLAs were quite narrow (1.04—1.14) and a Unear relationship between and the monomer-to-initiator ratio ([M]o/[I]o) existed at 0 °C. Dimeric complexes 4 and 6 were the... 

Hydrogen cyanide reacts with phenol in the presence of hydrochloric acid and aluminum chloride, forming 4-hydroxybenzaldehyde ... 

Magnesium and aluminum metal will react directly with phenol at its boiling point.1911 However, in both cases the inert oxide film must be mechanically removed or chemically dissolved. 

Strong chemical bonds between the adhesive and adherend help stabilize the interface and increase joint durability. Aluminum joints formed with phenolic adhesives generally exhibit better durability than those with epoxy adhesives. This is partially attributable to strongly interacting phenolic and aliphatic hydroxyl groups that form stable primary chemical bonds across the interface. 

Shipment, Storage, and Price, Tank cars and tank trailers, selected to prevent color formation, are of aluminum or stainless steel, or lined with epoxy or phenolic resins drums are lined with phenolic resins. Flexible stainless steel hose is used for transfer. Because of butanediol s high freezing point (about 20°C) tank car coil heaters are provided. The U.S. list price for bulk quantities in 1991 was about 2.18/kg, but heavy discounting was prevalent for large contracts. 

An oxidant. Combusdble when exposed to heat and flame. Moderate explosion hazard when exposed to heat or flame. Explosive reacdon with solid or concentrated alkali + heat (e.g., sodium hydroxide or potassium hydroxide), aluminum chloride + phenol (at 120°C), aniline + glycerol + sulfuric acid, nitric + sulfuric acid + heat. Forms explosive mixmres with aluminum chloride, oxidants (e.g., fluorodinitromethane, uranium perchlorate, tetranitromethane, sodium chlorate, nitric acid, nitric acid + water, peroxodisulfuric acid, dinitrogen tetraoxide), phosphorus pentachloride, potassium, sulfuric acid. Reacts violendy with aniline + glycerin, N2O, AgC104. To fight fire, use water, foam, CO2, dry chemical. Incompadble with potassium hydroxide. When heated to decomposidon it emits toxic flames of NOx. See also NITRO COMPOUNDS OF AROMATIC HYDROCARBONS. 

Derivation Condensation of rerr-pentanol with phenol with aluminum chloride catalyst. 

The hydrogen atom of the aquo group of (XII) is acidic the complex reacts with sodium hydroxide to yield an ill-characterized salt (10), and will condense with other acidic hydroxyl groups. Thus Owen and Kenney (268) have synthesized a series of aryloxy aluminum derivatives by the condensation of (XII) with various phenols. The complexes formed with phenol, p-phenylphenol, and p-methoxyphenol—(XIV), (XV), and (XVI)... 

Thus (XX) reacts with phenol in pyridine to form diphenoxysilicon phthalocyanine (XXII), with benzyl alcohol to form (XXIII), and with triphenylsilanol to form (XXIV) (168,170, 200). These complexes sublime readily without decomposition (cf. corresponding aluminum derivatives). Bis(diphenylmethylsiloxy)silicon phthalocyanine, which melts before subliming, is one of the very few metal phthalocyanines which actually melt (873). The siloxy complex (XXIV) may also be prepared in benzyl alcohol, thus implying that the Si—O—Si(Pc)—0—Si backbone is more stable than C—O—Si(Pc)—O—C. The dibenzyloxy derivative (XXIII) reacts with diphenylsilanediol to form bis(benzyloxydiphenylsiloxy)silicon phthalocyanine (XXV). 

Prepd by condensation of teri-pemanol or 2-methyl -3-butanol with phenol in the presence of aluminum chloride Huston, Hsieh, J. Am. Chem. Soc. 58, 439 (1936) Huston et al.. ibid. 67, 899 (1945). Physical properties Pardee, Wein-rich, lnd. Eng. Client. 36, 595 (1944). 

Reaction of imidoyl chlorides with phenols in the presence of aluminum chloride and subsequent hydrolysis also give phenolic ketones 571... 

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