Heteropolyacids and their salts supported on acidic ion-exchange resin as highly active solid-acid catalysts

Baba, Toshihide; Ono, Yoshio

doi:10.1016/s0166-9834(00)82639-1

Cited by 67 publications

(20 citation statements)

References 5 publications

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“…The acidic Cs + salt, Cs 2.5 H 0.5 PW 12 O 40 , was demonstrated as an excellent solid catalyst for various reactions [12,14]. The second method is to support HPAs on acidic or neutral supports such as SiO 2 [15,16], TiO 2 [17], ZrO 2 [18,19], acidic ion-exchange resin [20], or active carbon [21]. Impregnating HPAs on these supports significantly increases the specific surface area, which is very important for heterogeneous catalysis processes.…”

Section: Introductionmentioning

confidence: 99%

Progress of the Application of Mesoporous Silica-Supported Heteropolyacids in Heterogeneous Catalysis and Preparation of Nanostructured Metal Oxides

Ren

Yue

et al. 2010

Materials

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Mesoporous silica molecular sieves are a kind of unique catalyst support due to their large pore size and high surface area. Several methods have been developed to immobilize heteropolyacids (HPAs) inside the channels of these mesoporous silicas. The mesoporous silica-supported HPA materials have been widely used as recyclable catalysts in heterogeneous systems. They have shown high catalytic activities and shape selectivities in some reactions, compared to the parent HPAs in homogeneous systems. This review summarizes recent progress in the field of mesoporous silica-supported HPAs applied in the heterogeneous catalysis area and preparation of nanostructured metal oxides using HPAs as precursors and mesoporous silicas as hard templates.

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Section: Introductionmentioning

confidence: 99%

Progress of the Application of Mesoporous Silica-Supported Heteropolyacids in Heterogeneous Catalysis and Preparation of Nanostructured Metal Oxides

Ren

Yue

et al. 2010

Materials

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“…Although heteropolyacids are used in many acid catalyzed reactions, they possess some major disadvantages such as, (i) low surface area, (ii) high solubility in polar solvents, which makes their separation from the reaction medium difficult and (iii) deactivation during the reaction [44,45]. In order to improve the catalytic performance of heteropolyacids, several attempts have been made to heterogenize them by dispersing on suitable supports like silica (SiO 2 ) [46][47][48][49], active carbons [50,51] and ion exchange resins [52]. Among these supports, SiO 2 is widely used due to its chemical inertness towards heteropolyacids [53][54][55].…”

Section: Introductionmentioning

confidence: 99%

Solid Acid Catalysts: Modification of Acid Sites and Effect on Activity and Selectivity Tuning in Various Reactions

2009

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The effects of acidity and variation in concentration of acid sites of dodecatungstophosphoric acid (DTP), supported DTP and montmorillonite-K catalysts were studied for various organic reactions such as the hydroxyalkylation of phenols to bisphenols, intramolecular rearrangement of benzyl phenyl ether (BPE) to 2-benzyl phenol (2-BP) and selective cleavage of tert-butyldimethylsilyl (TBDMS) ether into the corresponding alcohol. Both dodecatungstophosphoric acid (DTP) impregnated on silica (SiO 2 ) and montmorillonite catalysts showed the highest catalyst activity with 90-95% selectivity to bisphenol for the hydroxyalkylation of phenols to give bisphenol. Temperature Programmed Desorption (TPD) of ammonia and activity results of various catalysts showed that an appropriate combination of both strong and weak acidic sites in the catalyst was highly desirable for high bisphenol selectivity. A 10% DTP/SiO 2 catalyst was found to be highly selective for the cleavage of TBDMS ether into the corresponding alcohol at room temperature giving a high TON of 9.5 9 10 5 even after the 4th recycle. DTP was also found to be a promising solid acid catalyst for the intramolecular rearrangement of BPE giving 2-BP.

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“…Esterifications with acetic acid are generally conducted in the liquid phase in the presence of a strong acid catalyst such as sulfuric acid (34). Increased reaction rates are reported when esterifications are carried out in the presence of heteropoly acids supported on macroreticular cation-exchange resins (35) and zeolite (36) catalysts in a heterogeneous process. Judging from the many patents issued in recent years, there appears to be considerable effort underway to find an appropriate solid catalyst for a reactive distillation esterification process to avoid the product removal difficulties of the conventional process.…”

Section: Esterificationmentioning

confidence: 99%

Amyl Alcohols

Papa¹

2003

Kirk-Othmer Encyclopedia of Chemical Technology

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Amyl alcohol describes any saturated aliphatic alcohol containing five carbon atoms. This class consists of three pentanols, four substituted butanols, and a disubstituted propanol, ie, eight structural isomers C 5 H 12 O: four primary, three secondary, and one tertiary alcohol. In addition, 2‐pentanol, 2‐methyl‐1‐butanol, and 3‐methyl‐2‐butanol have chiral centers and hence two enantiomeric forms. The odd‐carbon structure and the extent of branching provide amyl alcohols with unique physical and solubility properties and often offer ideal properties for solvent, surfactant, extraction, gasoline additive, and fragrance applications. Today the most important industrial process for amyl alcohol production is low pressure rhodium‐catalyzed hydroformylation (oxo process) of butenes. Mixtures of isomeric amyl alcohols (1‐pentanol and 2‐methyl‐1‐butanol) are often preferred because they are less expensive to produce commercially and have a more desirable combination of properties. With the exception of neopentyl alcohol (mp 53°C), the amyl alcohols are clear, colorless liquids under atmospheric conditions, with characteristic, slightly pungent and penetrating odors. Commercial primary amyl alcohol is a mixture of 1‐pentanol and 2‐methyl‐1‐butanol. Like the lower alcohols, amyl alcohols are completely miscible with numerous organic solvents and are excellent solvents for nitrocellulose, resin lacquers, higher esters, and various natural and synthetic gums and resins. However, in contrast to the lower alcohols, they are only slightly soluble in water. Important amyl alcohol reactions include dehydration, esterification, oxidation, amination, etherification, and condensation. Three significant commercial processes for the production of amyl alcohols include separation from fusel oils, chlorination of C‐5 alkanes with subsequent hydrolysis to produce a mixture of seven of the eight isomers (Pennsalt), and a low pressure oxo process. The oxo process is the principal one in practice today. The main effects of prolonged exposure to amyl alcohols are irritation to mucous membranes and upper respiratory tract, significant depression of the central nervous system, and narcotic effects from vapor inhalation or oral absorption. All the alcohols are harmful if inhaled or swallowed. 3‐Methyl‐1‐butanol has demonstrated carcinogenic activity in animal studies. The amyl alcohols are readily flammable substances; tert ‐amyl alcohol is the most flammable. Their vapors can form explosive mixtures with air. Amyl alcohols are best stored or shipped in either aluminum, lined steel, or stainless steel tanks.

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Heteropolyacids and their salts supported on acidic ion-exchange resin as highly active solid-acid catalysts

Cited by 67 publications

References 5 publications

Progress of the Application of Mesoporous Silica-Supported Heteropolyacids in Heterogeneous Catalysis and Preparation of Nanostructured Metal Oxides

Progress of the Application of Mesoporous Silica-Supported Heteropolyacids in Heterogeneous Catalysis and Preparation of Nanostructured Metal Oxides

Solid Acid Catalysts: Modification of Acid Sites and Effect on Activity and Selectivity Tuning in Various Reactions

Amyl Alcohols

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