Ammonium thiocyanate reagent

Ammonium sulfate reagent 89 Ammonium thiocyanate reagent 170 Amphetamines 45, 260, 299 Ampicillin 173,174 Amygdalin 179... 

In enamels for chemical plant such as autoclaves it is not only the degree of acid resistance which is important but also the freedom of the finish from minute flaws detectable by high frequency spark testing or chemical methods. The chemical methods depend upon a colour change when the reagent such as ammonium thiocyanate reacts with the iron exposed at the bottom of the pinhole or flaw in the finish. Alternatively, an electric cell can be formed via the exposed iron in the flaw and detected chemically. 

The following sections are concerned with the use of standard solutions of reagents such as silver nitrate, sodium chloride, potassium (or ammonium) thiocyanate, and potassium cyanide. Some of the determinations which will be considered strictly involve complex formation rather than precipitation reactions, but it is convenient to group them here as reactions involving the use of standard silver nitrate solutions. Before commencing the experimental work, the theoretical Sections 10.74 and 10.75 should be studied. 

Aminotrimethylenephosphonic acid 172 Ammonia 86,87 -, dipole moment 97 -, reagent 166 Ammonium cations 144 Ammonium rhodanide see Ammonium thiocyanate... 

Another reagent has been employed for the preparation of 381a <1997JME574>. In this case, ammonium thiocyanate provides the structural components for cyclization to occur. A number of other compounds (not shown here) were obtained in this way. 

A.3.5.6 Preparation of 20 Percent Solution of Ammonium Thiocyanate. Dissolve 60g of reagent grade ammonium thiocyanate (NH4SCN) in 240ml of distd w. Filter until clear and store 4.4.3.5.7 Preparation of 6N Hydrochloric Acid. 

Titrate the contents of the flask with 0.2N titanous chloride, adding 10 ml of 10% ammonium thiocyanate solut ion near the end point. Titrate slowly in the final stages allowing 10 seconds with good agitation between each drop. Carry out a blank determination on the reagents used and subtract from the above titer... 

Iron Add 2 mL of hydrochloric acid and 0.1 mL of nitric acid to the residue from Substances Not Precipitated by Hydrogen Sulfide (below), cover with a watch glass, and digest on a steam bath for 20 min. Remove the watch glass, and evaporate to dryness. Dissolve the residue in 1 mL of hydrochloric acid, and dilute to 60 mL with water. Dilute 5 mL of this solution to 40 mL with water, add 2 mL of hydrochloric acid, and dilute to 50 mL with water. Add 40 mg of ammonium peroxydisulfate crystals and 10 mL of ammonium thiocyanate TS, and mix thoroughly. Any red color produced within 1 h shall not exceed that produced by 0.033 mg of iron in an equal volume of solution containing the reagents used in the test. 

Iron Dilute 1 mL of the solution (100-mg sample) prepared for the Chloride test (above) to 40 mL with water. Add about 30 mg of ammonium persulfate crystals and 10 mL of ammonium thiocyanate TS. Any resulting red color does not exceed in intensity that produced by 2.0 mL of Iron Standard Solution (20 xg Fe) (see Solutions and Indicators) in an equal volume of a solution containing the same quantities of the reagents used in the test. 

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