Acid continued tartaric

If the heat be still longer continued tartaric acid loses half its basic water and becomes tap.thelicj acid—2 HO, C H, 0.,. 

A mixture of 10.0 g of 3-methylsulfinyl phenothiazine (MP 193° to 195°C), 6.1 g of finely powdered sodium hydroxide and 125 cc of toluene is boiled for 1 hour under reflux with a water separator on an oil bath kept at a temperature of 150°C, while the mixture is stirred. Without interrupting the boil a solution of 7.0 g of 2-(N-methvl-piperidyl-2 )-1-chloroethane (BP 84°C/10 mm Hg) in 10 cc of toluene is added dropwise in the course of 1 hour, after which boiling is continued for another 3 hours. When the reaction mixture has cooled it is first washed with 25 cc of water three times and then extracted with 75 cc of a 15% aqueous tartaric acid solution. The tartaric acid extract is shaken out with 25 cc... 

Oscillating rheometry continues to be useful in the study of AB cements, and has recently been used to give further insight into the role of (-1-)-tartaric acid in glass-ionomer cements (Hill Wilson, 1988). Further examples of its use are described in earlier chapters of this book. 

Ci A molecule with only an inversion center (center of symmetry) belongs to the group Ci. Example meso-tartaric acid in the conformation shown. Moving any point in the molecule along a straight line to this center, then continuing on an equal distance leaves the molecule apparently unchanged. 

It is well-known that catalytic amounts of aldehyde can induce racemization of a-amino acids through the reversible formation of Schiff bases.61 Combination of this technology with a classic resolution leads to an elegant asymmetric transformation of L-proline to D-proline (Scheme 6.8).62 63 When L-proline is heated with one equivalent of D-tartaric acid and a catalytic amount of n-butyraldehyde in butyric acid, it first racemizes as a result of the reversible formation of the proline-butyraldehyde Schiff base. The newly generated D-proline forms an insoluble salt with D-tartaric acid and precipitates out of the solution, whereas the soluble L-proline is continuously being racemized. The net effect is the continuous transformation of the soluble L-proline to the insoluble D-proline-D-tartaric acid complex, resulting in near-complete conversion. Treatment of the D-proline-D-tartaric acid complex with concentrated ammonia in methanol liberates the D-proline (16) (99% ee, with 80-90% overall yield from L-proline). This is a typical example of a dynamic resolution where L-proline is completely converted to D-proline with simultaneous in situ racemization. As far as the process is concerned, this is an ideal case because no extra step is required for recycle and racemization of the undesired enantiomer and a 100% chemical yield is achievable. The only drawback of this process is the use of stoichiometric amount of D-tartaric acid, which is the unnatural form of tartaric acid and is relatively expensive. Fortunately, more than 90% of the D-tartaric acid is recovered at the end of the process as the diammonium salt that can be recycled after conversion to the free acid.64... 

Use of unmodified starches in combination with mild acids and carbonates has been claimed.214 Starch moisture content should be no greater than 25%. Acids such as tartaric, citric or malic acids are added at levels between 0.2% and 7%, while the carbonate level is 0.1% to 2%, both based on total starch composition. The acid is stated to serve a two-fold function it depolymerizes the starch during extrusion via hydrolysis, improving expansion at the same time, it liberates carbon dioxide, which acts as a blowing agent, from the carbonate. A typical formula extruded in a twin-screw extruder at 170-195°C yielded a product with a density of approximately 1 lb/ft3 (16kg/m3) and resilience of 60-85%. The foam had a continuous skin with a closed cell structure. 

In addition to the use of malo-lactic fermentation in red wines, it also has been tried in V. vinifera cultivar Chardonnay. In the experiments known to the author, the use of the malo-lactic fermentation in Chardonnay has not proved successful from a sensory point of view. In general, the rise in pH was too great and the buffering capacity of the wine too great to permit adequate adjustment with tartaric acid. However, this work is continuing in conjunction with a number of variations in the local viticultural practices to produce Chardonnay of a lower total acidity. In addition to the use of malo-lactic fermentation for the reduction of the acidity, considerable work has been done in Washington on the use of acid reduction with calcium. Both calcium carbonate and the double salt precipitation, as described by Steele (23, 24), have been utilized. Some very significant successes have been achieved, particularly with the double salt method. 

Tris(ethylenediamine)chromium(III) chloride trihydrate (39.3 g., 0.10 mole) and 22.5 g. (0.15 mole) of (+)-tartaric acid, and a magnetic stirring bar, are placed in a 400-ml. beaker. A 100-ml. volume of water is added, and the mixture is dissolved with stirring. Immediately after the dissolution, 12.6 g. (0.30 mole) of IiOH-H20 is added with continued stirring. The hydroxide dissolves, and shortly after a yellow crystalline precipitate is formed. About 5 minutes after the addition of the hydroxide, 100 ml. of ethanol is added dropwise with continued stirring during a 15-minute period. The precipitate is filtered, and the filtrate is run directly into a mixture of 15 ml. (0.18 mole) of 12 M HC1 and 600 ml. of absolute ethanol. From this system a finely crystalline precipitate of impure (—)D-chloride separates out. The filter flask is replaced, and the crystals are washed with three 50-ml. portions of a 1 1 mixture of ethanol and water and dried in air. (Yield is 27-28 g.) The precipitate of (—)D-chloride from the filtrate is filtered, washed with three 50-ml. portions of ethanol, and dried in air. (Yield is 13-14 g.)... 

Cyanogen Compounds Mix 5 g of sample with 50 mL of water and 2 g of tartaric acid, and distill the mixture, collecting 25 mL of distillate below the surface of a mixture of 2 mL of 1 N sodium hydroxide and 10 mL of water contained in a small flask placed in an ice bath. Dilute the distillate to 50 mL with water, and mix. Add 12 drops of ferrous sulfate TS to 25 mL of the diluted distillate, heat almost to boiling, cool, and add 1 mL of hydrochloric acid. No blue color is produced. Higher Aromatic Hydrocarbons Extract 1 g of sample with 12 mL of cyclohexane in a continuous-extraction apparatus for 2 h. Place the extract in a Nessler tube and a solution of 100 (xg of quinine sulfate in 1000 mL of 0.1 N sulfuric acid in a matching Nessler tube. The extract shows no more color or fluorescence than does the solution when observed under ultraviolet light. 

Procedure Transfer 10.0 mL of Solution II into a 19- x 150-mm cuvette, and continue as directed under Standard Reference Curve, beginning with add 4.0 mL of a freshly prepared 1 20 sodium metavanadate solution.. .. From the reference curve, determine the weight, in milligrams, of tartaric acid in the final dilution, multiply this by 20, and divide the result by the weight of the original sample to obtain the percentage of tartaric acid. 

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