Precursors ethanol

One of the major problems associated with the hydrolysis of fluorinatcd compounds is the activation of fluoride substitution by per- or polyfliioroalkyl, perfltioroaryl groups, or double bonds linked to the same or adjacent carbon. However, hydrolysis not involving the C-F bond is widely used for the synthesis of 2-(perfluoroalkyl)ethanols, precursors to useful materials such as oil and water repellents, surfactants, and fire-fighting foams. The alcohols... 

Table 11.10 is a summary of the different conversion schemes and conditions for thermochemical ethanol formation discussed here. The primary routes to ethanol and ethanol precursors from synthesis gas are evident. It remains to be determined whether any of these technologies can be developed to produce low-cost thermochemical ethanol. 

Oxidation. Acetaldehyde is readily oxidised with oxygen or air to acetic acid, acetic anhydride, and peracetic acid (see Acetic acid and derivatives). The principal product depends on the reaction conditions. Acetic acid [64-19-7] may be produced commercially by the Hquid-phase oxidation of acetaldehyde at 65°C using cobalt or manganese acetate dissolved in acetic acid as a catalyst (34). Liquid-phase oxidation in the presence of mixed acetates of copper and cobalt yields acetic anhydride [108-24-7] (35). Peroxyacetic acid or a perester is beheved to be the precursor in both syntheses. There are two commercial processes for the production of peracetic acid [79-21 -0]. Low temperature oxidation of acetaldehyde in the presence of metal salts, ultraviolet irradiation, or osone yields acetaldehyde monoperacetate, which can be decomposed to peracetic acid and acetaldehyde (36). Peracetic acid can also be formed directiy by Hquid-phase oxidation at 5—50°C with a cobalt salt catalyst (37) (see Peroxides and peroxy compounds). Nitric acid oxidation of acetaldehyde yields glyoxal [107-22-2] (38,39). Oxidations of /)-xylene to terephthaHc acid [100-21-0] and of ethanol to acetic acid are activated by acetaldehyde (40,41). 

Pyrimido[4,5- f]pyrimidines may be used as pyrimidine precursors. Thus, the dihydro derivative (736) undergoes alkaline hydrolysis to the amide (737 R = PrCO) which may be deacylated in ethanolic hydrogen chloride to give 5-aminomethyl-2-propylpyrimidin-4-amine (737 R = H) (64CPB393) rather similarly, the pyrimidopyrimidinedione (738) reacts with amines to give, for example, 6-amino-5-benzyliminomethyl-l,3-dimethylpyrimidine-2,4(lFf,3Ff)-dione (739 R = CH2Ph) or the hydrazone (739 R = NH2) (74JCS(Pl)1812). 

It is interesting to note that Kulstad and Malmsten have utilized yet another method for introducing nitrogen into the crown precursors. They utilize sodium azide in DMSO to displace halogen from triethylene glycol dichloride. The bis-azide is then reduced using hydrogen sulfide in ethanol. ... 

The use of sodium tribromoacetate as the dibromocarbene precursor has been investigated and found to provide the Ciamician-Dennstedt product in higher yield than the traditional alkoxide/alcohol reaction conditions. Deprotonation of bromoform with sodium ethoxide in ethanol and reaction of the resultant carbene with 6 provides quinoline 9 in 9% yield thermolysis of sodium tribromoacetate in the presence of 6 furnishes 9 in 20% yield (Scheme 8.3.3). 

The preparaticai of 2 from the carbazole derivative 112 provided yet another alternative route (Scheme 14). The precursor 113 was obtained from 112 by heating with phenylhydrazine in ethanol in the presence of acetic acid, followed by... 

Ethanol s many uses can be conveniently divided into solvent and chemical uses. As a solvent, ethanol dissolves many organic-based materials such as fats, oils, and hydrocarbons. As a chemical intermediate, ethanol is a precursor for acetaldehyde, acetic acid, and diethyl ether, and it is used in the manufacture of glycol ethyl ethers, ethylamines, and many ethyl esters. 

Maleic anhydride is also a precursor for 1,4-butanediol through an esterification route followed by hydrogenation. In this process, excess ethyl alcohol esterifies maleic anhydride to monoethyl maleate. In a second step, the monoester catalytically esterifies to the diester. Excess ethanol and water are then removed by distillation. The ethanol-water mixture is distilled to recover ethanol, which is recycled ... 

The dried residue is dissolved in a chloroform/ethyl acetate mixture (95 5, v/v) and applied to a silica gel column (1.5 x 7 cm) that has been packed with chloroform. The column is washed with chloroform. Then the precursors are eluted with chloroform/ethanol (98 2, v/v). 

Fig. 9.13 Absorption spectrum of one of the luciferin precursors of Mycena cit-ricolor in methanol (dash-dot line, A.max 369 nm). The absorption and fluorescence emission spectra of the decylamine-activation product of the same precursor in neutral aqueous solution (solid lines abs. Amax 372 nm and fl. Xmax 460 nm), and in ethanol (broken lines abs. Amax 375 nm and fl. Amax 522 nm). The chemiluminescence spectrum of the same activation product (dotted line, A.max 580 nm). The dotted line (7max 320 nm) is the absorption spectrum of M. citricolor natural luciferin reported by Kuwabara and Wassink (1966).

Copper ore containing a deposit of aurlchalclte was obtained from Wards Natural Science Establishment. The mineral aurlchalclte crystallites were gently scraped from the ore and rinsed In ethanol prior to use. The synthetic precursor was prepared by copreclpltatlon from a mixture of IM Cu and IM Zn nitrate solutions, such that a Cu/Zn mole ratio of 30/70 was prepared, by dropwlse addition of IM Na2C03 at 90 C until the pH Increased from approximately 3 to 7. Calcination and reduction of the mineral were performed as In standard catalyst preparation procedures, which have been described In detail earlier (jL). ... 

The observed distribution can be readily explained upon assuming that the only part of polymer framework accessible to the metal precursor was the layer of swollen polymer beneath the pore surface. UCP 118 was meta-lated with a solution of [Pd(AcO)2] in THF/water (2/1) and palladium(II) was subsequently reduced with a solution of NaBH4 in ethanol. In the chemisorption experiment, saturation of the metal surface was achieved at a CO/Pd molar ratio as low as 0.02. For sake of comparison, a Pd/Si02 material (1.2% w/w) was exposed to CO under the same conditions and saturation was achieved at a CO/Pd molar ratio around 0.5. These observations clearly demonstrate that whereas palladium(II) is accessible to the reactant under solid-liquid conditions, when a swollen polymer layer forms beneath the pore surface, this is not true for palladium metal under gas-solid conditions, when swelling of the pore walls does not occur. In spite of this, it was reported that the treatment of dry resins containing immobilized metal precursors [92,85] with dihydrogen gas is an effective way to produce pol-5mer-supported metal nanoclusters. This could be the consequence of the small size of H2 molecules, which... 

Chemical reduction of metal salts in solution is the most widely used method of preparation of metal nanoparticles, especially in laboratories. In general, the reducing reagents are added into the solution of the precursor ions, but in some cases, a solvent works as a reductant. Various reducing reagents have been proposed to prepare metal nanoparticles. Ethanol or small alcohols can reduce precious metal ions such as Au, Pt", Pd, Ag, and so on [3j. Polymer-stabilized precious metal nanoparticles and their alloy particles can be used as good catalysts for various reactions. Polyols, such as ethylene glycol, were... 

Spirothiopyrans 45b including a benzopyrylium ring have been prepared in one step by condensation of 2-aminovinyl-3-formyl chromone-4-thione 47 with 1,2,3,3-tetramethylindolinium salts in ethanol (Scheme 25).90 The precursor 47 is prepared from 3-carboxymethylene-2-methyl-chromone-4-thione 48. First, oxidation of 48 with pyridinium dichromate in CH2C12, and then condensation with dimethyl formamide dimethyl acetal in benzene gave compound 47. 

An Ir11 intermediate in the carbonylation of ethanol, stabilized by the isoquinoline cation, has been isolated and characterized.496 IrCl3 31FO is the catalyst precursor and HI the promoter. The intermediate analyzes as (C9H8N)[Ir(CO)2l3(COC2H5)]. The magnetic moment is measured at 1.33 B.M., which is indicative of Ir1. 

Catalysts - A commercial Raney nickel (RNi-C) and a laboratory Raney nickel (RNi-L) were used in this study. RNi-C was supplied in an aqueous suspension (pH < 10.5, A1 < 7 wt %, particle size 0.012-0.128 mm). Prior to the activity test, RNi-C catalyst (2 g wet, 1.4 g dry, aqueous suspension) was washed three times with ethanol (20 ml) and twice with cyclohexane (CH) (20 mL) in order to remove water from the catalyst. RCN was then exchanged for the cyclohexane and the catalyst sample was introduced into the reactor as a suspension in the substrate. RNi-L catalyst was prepared from a 50 % Ni-50 % A1 alloy (0.045-0.1 mm in size) by treatment with NaOH which dissolved most of the Al. This catalyst was stored in passivated and dried form. Prior to the activity test, the catalyst (0.3 g) was treated in H2 at 250 °C for 2 h and then introduced to the reactor under CH. Raney cobalt (RCo), a commercial product, was treated likewise. Alumina supported Ru, Rh, Pd and Pt catalysts (powder) containing 5 wt. % of metal were purchased from Engelhard in reduced form. Prior to the activity test, catalyst (1.5 g) was treated in H2 at 250 °C for 2 h and then introduced to the reactor under solvent. 10 % Ni and 10 % Co/y-Al203 (200 m2/g) catalysts were prepared by incipient wetness impregnation using nitrate precursors. After drying the samples were calcined and reduced at 500 °C for 2 h and were then introduced to the reactor under CH. 

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