Iodides, acid preparation

Methylene iodide [75-11-6], CH2I2, also known as diio dome thane, mol wt 267.87, 94.76% I, mp 6.0°C, and bp 181°C, is a very heavy colorless Hquid. It has a density of 3.325 g/mL at 20°C and a refractive index of 1.7538 at 4°C. It darkens in contact with air, moisture, and light. Its solubiHty in water is 1.42 g/100 g H2O at 20°C it is soluble in alcohol, chloroform, ben2ene, and ether. Methylene iodide is prepared by reaction of sodium arsenite and iodoform with sodium hydroxide reaction of iodine, sodium ethoxide, and hydroiodic acid on iodoform the oxidation of iodoacetic acid with potassium persulfate and by reaction of potassium iodide and methylene chloride (124,125). Diiodoform is used for determining the density and refractive index of minerals. It is also used as a starting material in the manufacture of x-ray contrast media and other synthetic pharmaceuticals (qv). 

Kudryavtseva, L.I., Alkylation of phosphorus iodides. V. Preparative method for dialkylphosphinic acids, Zh. Obshch. Khim., 60, 833, 1990. 

Nakagome and co-workers effected the successful cyclization of N-ethyl-N-arylaminomethylenemalonates (749) in poly phosphoric acid, prepared from orthophosphoric acid and phosphorus pentoxide in polyphosphate ester (PPE), prepared from phosphorus pentoxide and anhydrous diethyl ether in chloroform in phosphoryl chloride on the action of boron trifluoride etherate on the action of acetic anhydride and concentrated sulfuric acid or on the action of phosphorus pentoxide in benzene [71GEP2033971, 71JHC357 76JAP(K) 18440]. Depending on the work-up process, l-ethyl-4-oxoquinoline-3-carboxylates (750, R1 = Et), l-ethyl-4-oxoquinoline-3-carboxylic acids (750, R2 = H) and 3-ethoxycarbonyl-4-chloroquinolinium iodides (751) were obtained. Only the cyclization of... 

Cadmium iodide is prepared by the addition of cadmium metal, or its oxide, hydroxide, nitrate or carbonate to hydriodic acid ... 

Copper(l) iodide is prepared by heating copper with iodine and concentrate hydriodic acid, HI. Another preparation route is precipitation of the salt by mixing aqueous solutions of potassium or sodium iodide with copper sulfate or any soluble copper(ll) salt ... 

Magnesium iodide is prepared by the reaction of magnesium oxide, hydroxide or carbonate with hydriodic acid, foUowed by evaporation of the solution and crystalhzation ... 

Sodium iodide is prepared by adding hydriodic acid or an acidic iodide solution to a solution of sodium hydroxide or sodium carbonate, followed by evaporation and crystallization ... 

Forty-seven grams (48 ml., 0.5 mole) of aniline is dissolved in 200 ml. of aqueous hydrochloric acid (prepared from equal volumes of concentrated acid and water) in a 2-1. beaker. The beaker is equipped with a mechanical stirrer and immersed in an ice-salt bath. After the solution has cooled to 5°, 36 g. (0.52 mole) of sodium nitrite dissolved in 1 1. of water is added slowly, with stirring, from a separatory funnel. The tip of the stem of the separatory funnel should dip well below the surface of the liquid. The rate of addition is adjusted to maintain the temperature below 10°. A drop of the reaction mixture is tested from time to time with starch-iodide paper (Note 2). The sodium nitrite solution is added until nitrous acid persists in the solution during a 5-minute interval. 

A variety of fluorinated alkenyl zinc reagents such as CF2=CFZnCl, CF2=CHZnCl, E and Z-RCF = CFZnCl have been prepared by the first method (Scheme 54). In the presence of palladium catalyst, these fluorinated alkenyl zinc reagents undergo cross-coupling reactions with aryl iodides, vinyl iodides, acid chlorides and 1-iodo-l-alkynes to give the corresponding fluorinated alkenyl derivatives [127, 146-153], which have been utilized in the synthesis of fluorinated codlemones [154]. Typical examples are outlined below (Scheme 55). 

The dichloride, when reduced by sulphurous acid, alkali sulphites or bisulphites, yields tellurium acetylpropionylmethane, from which the dibromide and di-iodide are prepared by the action of the corresponding halogen. 

Reaction XLVm. (a) Action of Alkali Cyanides on Alkyl and Acyl Halides. (Bl., [2], 50, 214.)—This reaction is capable of very wide application, all the simple alkyl halogen compounds, the acyl halides, and the halogen fatty acids come within its scope. The nitriles so formed yield acids by hydrolysis, so it is frequently the first step in the synthesis of an acid—the preparation and hydrolysis of the nitrile are often combined. The preparations of malonic, succinic, tricarballylic and other acids (Preparations 60, 61, 62) illustrate this. The extension of this reaction to acyl halides is important, and should be referred to, as should the interaction of silver cyanide, and alkyl iodides, to give isonitriles. Mercuric and silver cyanides, it may be noted, give with acyl chlorides and bromides better yields of normal acyl nitriles than do the alkali cyanides. 

The yield of constant-boiling acid is about 110 to 120 ml., or 90 per cent, based on the amount of iodine used. The product has a specific gravity of about 1.7 with a content of 57 per cent hydrogen iodide. If pure iodine and hydrogen sulfide are employed, the acid prepared in this way is quite pure except for a small amount of dissolved iodine produced by air oxidation. If a colorless product is desired, the distillation should be carried out in an atmosphere of hydrogen or carbon dioxide. 

Wear eye protection, laboratory coat, and nitrile rubber gloves. Prepare a 10% aqueous solution of the waste sodium chlorate. For each 10 mL of solution, slowly, and while stirring, add 44 mL of a 10% solution of sodium bisulfite (this allows about 50% excess of reducing agent). The continued presence of chlorate can be detected by adding, to 3 mL of the solution, a freshly prepared solution of potassium iodide (100 mg) in 3 mL of 3 M sulfuric acid (prepared by cautiously adding 0.5 mL of concentrated acid to 2.5 mL of cold water). An amber to brown color indicates the presence of chlorate. Add sodium bisulfite solution until the test is negative. Neutralize the acidic solution with sodium carbonate and discard into the drain with at least 50 times its volume of water.11 12... 

The method described is essentially that of Smith.1 Several other workers have used a similar method.2 Cetyl iodide has also been prepared by heating cetyl alcohol with yellow phosphorus and iodine in carbon disulfide solution,3 and by repeatedly passing dry hydrogen iodide acid into the molten alcohol and permitting the reaction mass to stand between additions.4... 

Sodium iodide, Nal.—The iodide is prepared by neutralizing sodium hydroxide or earbonate with hydriodic acid or by the action of iodine on sodium hydroxide, and reduction with charcoal of the iodate simultaneously formed or from sodium hydroxide and iodine in presence of iron-filings or ferrous iodide. 

Dimethylarsinous iodide was prepared from cacodylic acid and potassium iodide by the procedure given in reference 8. tThe checkers obtained 62%. 

A chiral Lewis acid prepared in situ from magnesium iodide and (/ ,f )-DPEN efficiently catalyzes asymmetric aza-Diels-Alder reaction of a methyl glyoxylate/p-anisidine derived imine with the Danishefsky diene to give the cyclic adduct in 97% ee (eq 11). ... 

The corresponding iodide is prepared in a similar manner to the bromide. It may be crystallised from benzene or acetone and melts at about 80° C. It is more readily decomposed than the bromide, and hydrochloric or acetic acids break it down to allyl alcohol and mercuric salts. The presence of the two hydroxyl groups has been shown by the fact that the iodide yields a dibenzoyl derivative, M.pt. 100° C. When the iodide is treated with iodine at 40° C. a liquid iodohydrine is obtained. 

The iodide is prepared from an alkaline solution of the nitrate by the addition of potassium iodide. It may be crystallised from boiling alkali. It has M.pt. 271° C., is practically insoluble in organic solvents, and remains unchanged when treated with 20 per cent, hydrochloric acid. With iodine in potassium iodide it reacts slowly, but iodine in. benzene at 140° C. gives di-ep2-iodohydrine, to which Stoehr assigns the structure ... 

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