Additions acetal

Reimschuessel and Deget polymerized caprolactam in sealed tubes containing about 0.0205 mol HjO per mole caprolactam. In addition, acetic acid (V), sebacic acid (S), hexamethylene diamine (H), and trimesic acid (T) were introduced as additives into separate runs. The following table lists (all data per mole caprolactam) the amounts of additive present and the analysis for end groups in various runs ... 

First,/)-hydroxybenzoic acid (HBA) and 6-hydroxy-2-naphthoic acid (HNA) are acetylated to produce the low melting acetate esters which are molten at 200°C. In an inert gas, the two monomers are melted together at 200°C. The temperature is raised to 250—280°C and acetic acid is coUected for 0.5 to 3 h. The temperature is raised to 280—340°C and additional acetic acid is removed in vacuum for a period of 10 to 60 min. The opalescent polymer melt produced is extmded through a spinning jet, foUowed by melt drawdown. The use of the paraUel offset monomer, acetylated HNA, results in the formation of a series of random copolyesters of different compositions, many of which faU within the commercially acceptable melting range of... 

In an integrated continuous process, cellulose reacts with acetic anhydride prepared from the carbonylation of methyl acetate with carbon monoxide. The acetic acid Hberated reacts further with methanol to give methyl acetate, which is then carbonylated to give additional acetic anhydride (100,101). 

Addition, acetic acid to bicyclo[2.2.1]-hepta-2,5-diene to give nortri-cyclyl acetate, 46, 74 1,2,3-benzothiadiazole 1,1-dioxide to cyclopentadiene, 47, 8 benzyne to tetraphenylcyclopentadie-none, 46,107 Br, F to 1-heptene, 46,10 carbon tetrachloride to olefins, 46, 106... 

FIGURE 11.16 (a) A saturated solution of zinc acetate in water, (b) When additional acetate ions are added (as a single crystal of solid sodium acetate in the spatula shown in part (a)), the solubility ot the zinc acetate is significantly reduced and more zinc acetate precipitates. 

Additional Acetic Acid Added Post-Dissolution Water volume... 

Addition, acetic acid to bicyclo[2.2.1]-hepta-2,5-diene to give nortri-cyclyl acetate, 46, 74... 

Azidation.1 Arylsulfonyl azides generally react with enolates to effect net diazo transfer, but this hindered and electron-rich azide can effect azide transfer at the expense of diazo transfer. The nature of the enolate counterion also plays a role, with K being more effective than Na. In addition, acetic acid (or KOAc) is required as the quench for decomposition of the triazine intermediate to the azide with elimination of the arylsulfinic acid, ArS(0)0H. By use of these conditions, chiral N-acyloxazolidones such as 2 undergo diastereoselective azidation to give the azides 3 in 75-90% yield and in high optical purity (>91 9). These... 

Acetic acid occurs naturally in many plant species including Merrill flowers Telosma cordata), in which it was detected at a concentration of 2,610 ppm (Furukawa et al., 1993). In addition, acetic acid was detected in cacao seeds (1,520 to 7,100 ppm), celery, blackwood, blueberry juice (0.7 ppm), pineapples, licorice roots (2 ppm), grapes (1,500 to 2,000 ppm), onion bulbs, oats, horse chestnuts, coriander, ginseng, hot peppers, linseed (3,105 to 3,853 ppm), ambrette, and chocolate vines (Duke, 1992). 

As in all large-scale industrial processes, the formation of the cellulose esters involves recovery of materials. Acetic anhydride is generally employed. After reaction, acetic acid and solvent are recovered. The recovered acetic acid is employed in the production of additional acetic anhydride. The recovered solvent is also reintroduced after treatment. 

The ratio of alcohol to acetate depends upon workup procedure, which differed in the two cases. In addition, acetates of benzylic alcohols typically break down under electron impact by a low energy process to produce ketene and the corresponding alcohol ion. The peak at the parent mass of the alcohol, throughout this work, most likely contains a contribution so derived from the acetate. A careful distinction between the alcohol and acetate was not deemed important for our purposes, so... 

Hydrochloric acid added to a solution containing acetic acid and sodium acetate is neutralized by the sodium acetate to form additional acetic acid. 

SYNTHESIS A solution of 0.4 g 1 -(2,5-dimethoxy-4-methylphenyl)-1 -methoxy-2-nitroethane (see preparation in the recipe for BOD) in 3.0 mL acetic acid was heated to 100 °C on a steam bath. There was added 1.0 g powdered zinc, followed by additional acetic acid as needed to maintain smooth stirring. After0.5 h there was... 

Preparation from Hydrazine Hydrate. Hydrazine hydrate may be substituted for hydrazine sulfate in the preparation of biurea. In this case it is necessary to supply enough additional acetic acid to compensate for the absence of sulfuric acid. Thus, 29 g. of 85% hydrazine hydrate (0.5 mol) and 90 g. of glacial acetic acid (1.5 mol) are dissolved in 500 ml. of water. Eighty-nine grams of potas-... 

Acetal translucent crystalline polymer is one of the stiffest TPs available. It provides excellent hardness and heat resistance, even in the presence of solvents and alkalies. Its low moisture sensitivity and good electrical properties permit direct competition with die-cast metal in a variety of applications. In addition, acetal has extremely high creep resistance and low permeability. Acetal is also available as a copolymer (Hoechst Celanese Corp. s Celcon) for improved processability. The homopolymer (DuPont s Delrin) has a very low coefficient of friction and its resistance to abrasion is second only to nylon 6/6. Acetals are frequently blended with fibers such as glass or fluorocarbon to enhance stiffness and friction properties. Acetal is not particularly weather-resistant, but grades are available with UV stabilizers for improved outdoor performance. Acetal, whether homopolymer or copolymer, is not used to any significant degree in forming structural foams. 

A similar approach was described by Kim et al. <01MI1403> to build the Furstner synthon from the vinylogous amide 9, previously described, and the commercially available dimethyl aminomalonate hydrochloride as building block for pyrrole systems. The cyclocondensation reaction between the vinylogous amide 9 and dimethyl aminomalonate hydrochloride was performed in acetic acid at room temperature to yield the presumed Intermediate 12 via an acid-catalyzed nucleophilic substitution reaction. The mixture was then diluted with additional acetic acid and heated under reflux to facilitate the intramolecular ring closure and the loss of the methoxycarbonyl moiety to produce the desired pyrrole. Formation of lamellarin O dimethyl ether was achieved as in the Furstner approach <95JOC6637>. 

Furthermore, nonaqueous, especially nonprotic, solvents allow Pictet-Spengler condensation reactions to occur with acid>labile aldehydes e.g. when bearing additional acetal functions) and may significantly influence the stereoselectivity (see below). 

Exchangeable species. This phase contains weakly bound (electrostatically) metal species that can be released by ion-exchange with cations such as Ca2+, Mg2+ or NH4"1". Ammonium acetate is the preferred extractant as the complex-ing power of acetate prevents re-adsorption or precipitation of released metal ions. In addition, acetic acid dissolves the exchangeable species, as well as more tightly bound exchangeable forms. 

A remarkable property of crown ethers is that they allow inorganic salts to be dissolved in nonpolar organic solvents, thus permitting many reactions to be carried out in nonpolar solvents that otherwise would not be able to take place. For example, the Sn2 reaction of 1-bromohexane with acetate ion poses a problem because potassium acetate is an ionic compound that is soluble only in water, whereas the alkyl halide is insoluble in water. In addition, acetate ion is an extremely poor nucleophile. 

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