Zinc, Acetate

PhEur Zinc acetas dihydricus USP Zinc acetate 

Acetic acid, zinc salt dicarbomethoxy zinc zinc (II) acetate zinc diacetate zinc ethanoate. 

Emollient emulsion stabilizer gelling agent opacifier stabilizing agent. 

Zinc acetate has been used as an excipient in a variety of pharmaceutical formulations including topical gels, lotions, and solutions, and subcutaneous injections. It has also been investigated for use in an oral controlled-release formulation for water-soluble drugs in combination with sodium alginate and xanthan gum.  

Therapeutically, zinc acetate has been used in oral capsules for the treatment of Wilson s disease.Zinc acetate has also 

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Raw Material. PVA is synthesized from acetjiene [74-86-2] or ethylene [74-85-1] by reaction with acetic acid (and oxygen in the case of ethylene), in the presence of a catalyst such as zinc acetate, to form vinyl acetate [108-05-4] which is then polymerized in methanol. The polymer obtained is subjected to methanolysis with sodium hydroxide, whereby PVA precipitates from the methanol solution. 

Vinyl ethers are prepared in a solution process at 150—200°C with alkaH metal hydroxide catalysts (32—34), although a vapor-phase process has been reported (35). A wide variety of vinyl ethers are produced commercially. Vinyl acetate has been manufactured from acetic acid and acetylene in a vapor-phase process using zinc acetate catalyst (36,37), but ethylene is the currently preferred raw material. Vinyl derivatives of amines, amides, and mercaptans can be made similarly. A/-Vinyl-2-pyrroHdinone is a commercially important monomer prepared by vinylation of 2-pyrroHdinone using a base catalyst. 

A process based on saponification of ethylene—acrylate ester copolymers has been practiced commercially in Japan (29). The saponification naturally produces fully neutralized polymer, and it is then necessary to acidify in order to obtain a pardy neutralized, melt-processible product. Technology is described to convert the sodium ionomer produced by this process to the zinc type by soaking pellets in zinc acetate solution, followed by drying (29). 

PhenoHc resins are prepared with strong acid or alkaline catalysts. Occasionally, weak or Lewis acids, such as zinc acetate, are used for specialty resins. 

Zinc acetate catalyst produces essentially 100% o-methylol phenol (8) in the first step. The second step gives an approximately equal quantity of 2,2 -(5, 45%) and 2,4 -diphenyhnethylene (6, 45%) bridges, indicating Htde chelate-directing influence. In addition, a small quantity (10%) of methylene ether units (9) (diben2yl ether) is observed at moderate reaction temperature. 

Introduction of a 3-bromosubstituent onto thiophene is accompHshed by initial tribromination, followed by reduction of the a-bromines by treatment with zinc/acetic acid, thereby utilizing only one of three bromines introduced. The so-called halogen dance sequence of reactions, whereby bromothiophenes are treated with base, causing proton abstraction and rearrangement of bromine to the produce the most-stable anion, has also been used to introduce a bromine atom at position 3. The formation of 3-bromotbiopbene [872-31-1] from this sequence of reactions (17) is an efficient use of bromine. Vapor-phase techniques have also been proposed to achieve this halogen migration (18), but with less specificity. Table 3 summarizes properties of some brominated thiophenes. 

Chemsweet from C. E. Natco is another, H7S-only process. It uses a water dispersion of zinc oxide and zinc acetate to oxidize H7S and form zinc sulfide. The process... 

It is reported that the yield is increased to 75 per cent by adding sodium acetate to the zinc dust reduction mixture to form a complex with the zinc acetate and so increase its solubility, and by adding the solution of the nitroso compound to the... 

Vapour phase synthesis may be carried out by passing a mixture of acetylene and acetic acid through a reaction tube at 210-215°C. Typical catalysts for this reaction are cadmium acetate, zinc acetate and zinc silicate. The monomer in each of the above mentioned processes is purified by distillation. 

Pigments or dyes may be added at this stage and where clear water-white sheet is required a small amount of a soluble violet dye is added to offset the faintly yellow colour of the natural mix. Stabilisers such as zinc oxide, zinc acetate or urea may be added to prevent the composition from developing acidity. 

Resoles are usually those phenolics made under alkaline conditions with an excess of aldehyde. The name denotes a phenol alcohol, which is the dominant species in most resoles. The most common catalyst is sodium hydroxide, though lithium, potassium, magnesium, calcium, strontium, and barium hydroxides or oxides are also frequently used. Amine catalysis is also common. Occasionally, a Lewis acid salt, such as zinc acetate or tin chloride will be used to achieve some special property. Due to inclusion of excess aldehyde, resoles are capable of curing without addition of methylene donors. Although cure accelerators are available, it is common to cure resoles by application of heat alone. 

Chemical Designations - Synonyms Acetic acid, zinc salt Dicarbomethoxyzine Zinc acetate dehydrate Zinc diacetate Chemical Formula Zn(CWtf) or Zn(CWtf) tfO. 

Recently, in extending the reaction to aliphatic glycols, Ghera observed that p-nitrobenzoate esters gave better results than acetates, and that zinc acetate could be substituted for activated zinc. He has proposed that the rearrangement is a heterogeneous catalytic process, with the zinc acting as a Lewis acid ... 

Ordinarily the zinc-acetic acid system will not react with a 21-acetoxy-20-ketone however, if a A -double bond is also present, the 21-acetoxyl group is removed in high yield at room temperature in 3 min. Increasing the time of reaction causes subsequent reduction of the 20-ketone to hydroxyl. 

The intermediate hydroperoxide is sufficiently stable to be isolated, and reduction with any one of a number of reagents (zinc-acetic acid is preferred) then gives the 17a-hydroxy-20-keto compound. 

A A -S-ketone will survive this treatment. By contrast, treatment of a 17a, 21-dihydroxy-20-one with zinc-acetic acid produces a 21-acetoxy-20-ketone, probably via a Mattox-Kendall rearrangement (see below)... 

The reaction is generally carried out in an alcoholic solvent, resulting in formation of the acetal the general scheme is called the Mattox rearrangement, and the yields are usually high. If a nonalcoholic solvent and acid are used, the aldehyde is obtained directly, but in lower yield. However, the use of zinc acetate as catalyst instead of an acid permits isolation of the aldehyde in ca. 50 % yield. Tire use of refluxing acetic acid alone... 

Under different conditions, that is in refluxing glacial acetic acid and zinc acetate, 2,4-dimethylpyrrole yields tetramethylpyrrocoline (1). Under reducing conditions, with zinc and acetic acid, 2,5-... 

Myrcene, C10H16, is found in oil of bay leaves and is isomeric with jS-ocimene (Problem 14.48). It has an ultraviolet absorption at 226 nm and can be catalytically hydrogenated to yield 2( 6-dimethyloctane. On ozonolysis followed by zinc/acetic acid treatment, myrcene yields formaldehyde, acetone, and 2-oxopentanedial ... 

Hydrocarbon A, CLoIi14, has a UV absorption at Araax = 236 nm and gives hydrocarbon B, C10Hig, on catalytic hydrogenation. Ozonolysis of A followed by zinc/acetic acid treatment yields the following diketo dialdehyde ... 

Solution B dissolve 60 g crystallised zinc acetate Zn(C2H302)2,3H20 in 3 mL glacial acetic acid and 100 mL of water. 

Spectrophotometers Units of length, 646, 647 of mass, 75 of volume, xxix, 78 Universal indicators 268 Uranium, D. of by cupferron, (g) 471 by oxine, (g) 474 Uranyl zinc acetate 467 Urea in homogeneous pptn., 426, 453... 

A PEIT of 50/50 (molar ratio) composition is synthesized by a two-step reaction sequence as follows. In the first step, 97.10 g (0.5 mol) dimethyl terephthalate (DMT), 97.10 g (0.5 mol) dimethyl isophthalate (DMI), 136.55 g (2.2 mol) 1,2-ethanediol, and zinc acetate dihydrate ester interchange catalyst (2.7 x 10 4% mass of the total amount of DMI and DMT mixture) are weighed into a threenecked flask fitted with a mechanical stirrer, a nitrogen inlet, and a condenser. The medium is stirred for 2.0-2.5 h at 180-210°C under nitrogen. Ninety-two percent of the theoretical amount of methanol is removed by distillation. In the second step, antimony acetate polycondensation catalyst and trimethyl phosphate thermal stabilizer (9.9 x 10-4 and 1.5 x 10 3% mass of the total amount of DMI... 

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