Direct acetone

Table 1 lists crude extracts (mother liquor) of the plants studied however, the lignans were generally isolated after re-extractions rather than directly from the crude extracts. Extraction and isolation details are provided in the references [68-88] given in Table 1. As seen from the table, crude extracts were prepared with a polar solvent, mostly ethanol, sometimes water, but higher diversity was obtained by working with a direct acetone extract of T. maireii twigs, considering the number of the lignans isolated. An early study of Taxus lignans by Erdtman and Tsuno reported a brief comparative examination of several Taxus woods [67].

Direct acetonation of L-sorbose is employed in the vitamin C synthesis. However, the diacetone-L-sorbose which is obtained is frequently contaminated by varying amounts of monoacetone-L-sorbose. The amount of monoacetone-L-sorbose87b in the diacetone derivative has been determined by petroleum ether extraction, followed by decomposition of the monoacetone derivative to acetone, which is determined iodimetrically. 

The crossed condensation of an aromatic aldehyde with a ketone usually gives a high yield of the unsaturated ketone directly. Acetone is condensed with either one or two molecules of benzaldehyde to give ben-zalacetone (68%) or dibenzalacetone (94%), respectively. Alkyl stytyl ketones, CjHs CH = C(R)COR, have been prepared from benzalde-hyde and higher ketones in the presence of hydrochloric acid or alkali hydroxide. Substituents on the phenyl group include methyl, hydroxyl, methoxyl, and nitro groups. A survey of condensa-... 

Scheme 9.7 Prolinethioamide-catalysed direct acetone aldolisation.

Place 0 5 ml. of acetone, 20 ml. of 10% aqueous potassium iodide solution and 8 ml. of 10% aqueous sodium hydroxide solution in a 50 ml. conical flask, and then add 20 ml. of a freshly prepared molar solution of sodium hypochlorite. Well mix the contents of the flask, when the yellow iodoform will begin to separate almost immediately allow the mixture to stand at room temperature for 10 minutes, and then filter at the pump, wash with cold w ater, and drain thoroughly. Yield of Crude material, 1 4 g. Recrystallise the crude iodoform from methylated spirit. For this purpose, place the crude material in a 50 ml. round-bottomed flask fitted with a reflux water-condenser, add a small quantity of methylated spirit, and heat to boiling on a water-bath then add more methylated spirit cautiously down the condenser until all the iodoform has dissolved. Filter the hot solution through a fluted filter-paper directly into a small beaker or conical flask, and then cool in ice-water. The iodoform rapidly crystallises. Filter at the pump, drain thoroughly and dry. 

Acetamide is thus obtained as a colourless crystalline solid, which has a characteristic odour of mice, stated to be due to the presence of small quantities of methylacetamide, CH3CONHCH3. The acetamide can be purified and rendered odourless by re-crystallisation from acetone, and then has m.p. 82°, b.p. 223°. If this recrystallisation is contemplated, the distilled material should be collected directly into a small weighed beaker or conical flask, so that the solidified acetamide can be readily broken up and removed. 

Place in the flask 2 g. of benzophenone, 15 ml. of isopropanol and 2 5 g. of aluminium isopropoxide. This mixture has now to be heated gently under reflux so that the temperature registered by the thermometer in the column does not exceed 80°, i.e., so that only acetone distils. For this purpose, the flask should preferably be heated in an oil-bath direct heating, even over an asbestos sheet, may cause local overheating and decomposition the use of a water-bath on the other hand may make the column undesirably damp. 

A) Toluene -sulphonates. For directions, using an acetone solution of toluene-/) Sulphonyl chloride, see p. 249 use o 3-o 5 g. of the phenol. Note that the chloride should be dissolved in a minimum of acetone, otherwise separation of the ester may be slow and incomplete. 

Bisulphite addition compound. Shake 1 ml. of acetone with 0 5 ml. of a saturated solution of NaHS03. A white precipitate is formed, the mixture becoming warm and then, on cooling, almost solid. Acetophenone and benzophenone, having the >CO group directly joined to tlie benzene ring, do not respond to the test (p- 257). 

The more extensive problem of correlating substituent effects in electrophilic substitution by a two-parameter equation has been examined by Brown and his co-workers. In order to define a new set of substituent constants. Brown chose as a model reaction the solvolysis of substituted dimethylphenylcarbinyl chlorides in 90% aq. acetone. In the case ofp-substituted compounds, the transition state, represented by the following resonance structures, is stabilized by direct resonance interaction between the substituent and the site of reaction. 

The suitability of the model reaction chosen by Brown has been criticised. There are many side-chain reactions in which, during reaction, electron deficiencies arise at the site of reaction. The values of the substituent constants obtainable from these reactions would not agree with the values chosen for cr+. At worst, if the solvolysis of substituted benzyl chlorides in 50% aq. acetone had been chosen as the model reaction, crJ-Me would have been —0-82 instead of the adopted value of —0-28. It is difficult to see how the choice of reaction was defended, save by pointing out that the variation in the values of the substituent constants, derivable from different reactions, were not systematically related to the values of the reaction constants such a relationship would have been expected if the importance of the stabilization of the transition-state by direct resonance increased with increasing values of the reaction constant. 

To a solution of ethylnagnesium bromide in 350 ml of THF, prepared from 0.5 mol of ethyl bromide (see Chapter 11, Exp. 6) was added in 10 min at 10°C 0.47 mol of 1-hexyne (Exp. 62) and at 0°C 0.47 mol of trimethylsilylacetylene (Exp. 31) or a solution of 0.60 mol of propyne in 70 ml of THF (cooled below -20°C). With trimethyl si lylacetylene an exothermic reaction started almost immediately, so that efficient cooling in a bath of dry-ice and acetone was necessary in order to keep the temperature between 10 and 15°C. When the exothermic reaction had subsided, the mixture was warmed to 20°C and was kept at that temperature for 1 h. With 1-hexyne the cooling bath was removed directly after the addition and the temperature was allowed to rise to 40-45°C and was maintained at that level for 1 h. 

The first member of the series. 2-imino-3,4-dimethyl-4-thiazoline (363) is obtained when the di-HBr salt of bis(methylformamidine)disulfide (362i is refluxed for 16 hr in acetone (Scheme 209) (700). The most common preparative methods involve direct heterocyclization by the Hantzsch method (see Chapter II. Section II.4), though the mechanism of this reaction suggests certain limitations according to the respective natures of R2, R3, and in 364 (Scheme 210). 

PROPENE The major use of propene is in the produc tion of polypropylene Two other propene derived organic chemicals acrylonitrile and propylene oxide are also starting materials for polymer synthesis Acrylonitrile is used to make acrylic fibers (see Table 6 5) and propylene oxide is one component in the preparation of polyurethane polymers Cumene itself has no direct uses but rather serves as the starting material in a process that yields two valuable indus trial chemicals acetone and phenol... 

Acetaldehyde, first used extensively during World War I as a starting material for making acetone [67-64-1] from acetic acid [64-19-7] is currendy an important intermediate in the production of acetic acid, acetic anhydride [108-24-7] ethyl acetate [141-78-6] peracetic acid [79-21 -0] pentaerythritol [115-77-5] chloral [302-17-0], glyoxal [107-22-2], aLkylamines, and pyridines. Commercial processes for acetaldehyde production include the oxidation or dehydrogenation of ethanol, the addition of water to acetylene, the partial oxidation of hydrocarbons, and the direct oxidation of ethylene [74-85-1]. In 1989, it was estimated that 28 companies having more than 98% of the wodd s 2.5 megaton per year plant capacity used the Wacker-Hoechst processes for the direct oxidation of ethylene. 

Butane-Naphtha Catalytic Liquid-Phase Oxidation. Direct Hquid-phase oxidation ofbutane and/or naphtha [8030-30-6] was once the most favored worldwide route to acetic acid because of the low cost of these hydrocarbons. Butane [106-97-8] in the presence of metallic ions, eg, cobalt, chromium, or manganese, undergoes simple air oxidation in acetic acid solvent (48). The peroxidic intermediates are decomposed by high temperature, by mechanical agitation, and by action of the metallic catalysts, to form acetic acid and a comparatively small suite of other compounds (49). Ethyl acetate and butanone are produced, and the process can be altered to provide larger quantities of these valuable materials. Ethanol is thought to be an important intermediate (50) acetone forms through a minor pathway from isobutane present in the hydrocarbon feed. Formic acid, propionic acid, and minor quantities of butyric acid are also formed. 

Production of acetone by dehydrogenation of isopropyl alcohol began in the early 1920s and remained the dominant production method through the 1960s. In the mid-1960s virtually all United States acetone was produced from propylene. A process for direct oxidation of propylene to acetone was developed by Wacker Chemie (12), but is not beheved to have been used in the United States. However, by the mid-1970s 60% of United States acetone capacity was based on cumene hydroperoxide [80-15-9], which accounted for about 65% of the acetone produced. 

Direct oxidation of hydrocarbons and catalytic oxidation of isopropyl alcohol have also been used for commercial production of acetone. 

C depending on the reference consulted). Fires may be controlled with carbon dioxide or dry chemical extinguishers. Recommended methods of handlings loadings unloadings and storage can be obtained from Material Safety Data Sheets and inquiries directed to suppHers of acetone. 

Figure 8 illustrates one of the processing schemes used for separating various components in a hydrocarbon-containing plant. Acetone extraction removes the polyphenols, glycerides, and sterols, and benzene extraction removes the hydrocarbons. If the biomass species in question contain low concentrations of the nonhydrocarbon components, exclusive of the carbohydrate and protein fractions, direct extraction of the hydrocarbons with benzene or a similar solvent might be preferred. 

Tris(2,4-pentanedionato)iron(III) [14024-18-1], Fe(C H202)3 or Fe(acac)3, forms mby red rhombic crystals that melt at 184°C. This high spin complex is obtained by reaction of iron(III) hydroxide and excess ligand. It is only slightly soluble in water, but is soluble in alcohol, acetone, chloroform, or benzene. The stmcture has a near-octahedral arrangement of the six oxygen atoms. Related complexes can be formed with other P-diketones by either direct synthesis or exchange of the diketone into Fe(acac)3. The complex is used as a catalyst in oxidation and polymerization reactions. 

Direct oxidation yields biacetyl (2,3-butanedione), a flavorant, or methyl ethyl ketone peroxide, an initiator used in polyester production. Ma.nufa.cture. MEK is predominandy produced by the dehydrogenation of 2-butanol. The reaction mechanism (11—13) and reaction equihbtium (14) have been reported, and the process is in many ways analogous to the production of acetone (qv) from isopropyl alcohol. 

Mesityl oxide can also be produced by the direct condensation of acetone at higher temperatures. This reaction can be operated ia the vapor phase over 2iac oxide (182), or 2iac oxide—2irconium oxide (183), or ia the Hquid phase over cation-exchange resia (184) or 2irconium phosphate (185). Other catalysts are known (186). 

Considerable research is currendy directed toward development of novel technologies that may present economic advantages with respect to the conventional acetone cyanohydrin (ACH) route. Mitsubishi Gas Chemical Co. has developed and patented a modified acetone cyanohydrin-based route... 

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