Sodium cyanate

Sodium cyanate (NaOCN) is a reagent used to prepare ureas and organic isocyanates. Despite the name, it's not very toxic. It is possible to reduce sodium cyanate to the infamous poison sodium cyanide, but I won't be doing this for obvious reasons. I'm interested in using sodium cyanate to synthesize semicarbazide.

I prepared sodium cyanate from sodium carbonate and urea.

To a metal pot I added 13.4g of anhydrous sodium carbonate. I heated the pot strongly for 10 minutes to ensure the sodium carbonate was truly dry. After this, I added 5.75g of urea with stirring.
The urea almost immediately melted and decomposed. The urea addition must be performed outside because large amounts of toxic ammonia gas are produced. Anyway, I added 2 more 5.75g portions of urea separately with stirring. After all the urea had been added (and the mixture was dry) I added 90ml of water. Glacial acetic acid was added until the mixture reached pH 6. I filtered the mixture, collecting the clear filtrate. Then I added 100ml of ethanol and stirred.

A fine precipitate of sodium cyanate formed. I collected the sodium cyanate via filtration and dried the product. 2.43g of sodium cyanate was obtained.

(NH2)2CO ==> HOCN + NH3   /   2 HOCN + Na2CO3 ==> 2 NaOCN + H2O + CO2

Sodium bromate

Sodium bromate is an interesting oxidizer used in industrial batch dyeing. Weirdly enough, solutions of it can dissolve gold so it's sometimes used in gold mining. Sodium bromate must be handled with care as it's a possible carcinogen. The easiest way to make sodium bromate is using electrochemistry. I tried this method out.

To a 300ml beaker I added 50ml of saturated sodium bromide solution and a pinch of sodium dichromate. I then electrolyzed the mixture for 3 hours and 10 minutes. The power source was 12 volts DC at 24 amps. A carbon anode and a steel cathode were used. Anyway, after the electrolysis, the mixture was filtered to remove carbon particles and then chilled down to 10 C. Nice white crystals of sodium bromate precipitated as the mixture cooled. I filtered the mixture again to collect the sodium bromate. Then I dried the product. I was left with 1.23g of sodium bromate.

left = dried sodium bromate    right = pyrotechnic with sodium bromate and Mg

anode:  2 Br- ==> Br2 + 2 e-   /   cathode: H2O + 2 e- ==> 2 OH- + H2

Br2 + 2 OH- ==> BrO- + Br- + H2O  /  3 BrO- ==> BrO3- + Br-  /   Na+ + BrO3- ==> NaBrO3

1,3,5-Trichlorohexahydrotriazine

1,3,5-Trichlorohexahydrotriazine (C3H6N3Cl3) is a mildly energetic compound prepared from hexamine. It's a yellow-white solid which generates chlorine on contact with hydrochloric acid. It's also a very unstable compound. Aside from this, not much is known about it.

To synthesize it I started with 2.7g of hexamine which I dissolved in 25ml of water in a beaker. To a separate beaker I added 60ml of  5% sodium hypochlorite solution and 80ml of 5% acetic acid. I then poured the hexamine solution into the hypochlorite/acetic acid mix. Immediately a white precipitate of the product formed.

The precipitate was filtered off. The product tends to decompose to a yellow oil while drying. So every time I try drying the product, it completely decomposes and I am left with nothing. Here's a picture of some wet 1,3,5-trichlorohexahydrotriazine:

I'm not sure what the equation is sadly.

Bromoform

Tribromomethane or bromoform is a toxic brominated hydrocarbon. It's analogous to chloroform but with the three chlorine atoms replaced with three bromines. Its not a very useful compound to have but its still interesting. I made some because I had recently obtained some sodium bromide and wanted to use it for something.

I chose to use the haloform reaction to make bromoform.

To make bromoform I started by adding 10g of sodium bromide and 150ml of water to a conical flask. I then poured in 205ml of 5% sodium hypochlorite bleach. The mixture was stirred, and I added 4ml of acetone with 10ml of water. I stirred the mixture well, then set it aside for 5 hours. After this, little drops of bromoform could been seen at the bottom of the flask. I shook the flask and the drops of bromoform came together into a homogeneous liquid. The little layer of bromoform at bottom was collected with a syringe. I determined I had 0.6ml of bromoform which is a 12.5% yield.

If you look carefully you can see the lower bromoform layer.

I attribute my terrible yield to a lot of the bromoform drops not collecting together as well as my clumsy collection of the product with the syringe.

NaBr + NaOCl ==> NaOBr

(CH3)2CO + 3 NaOBr + H2O ==> CHBr3 + CH3COOH + 3 NaOH

Chromium chlorate

Chromium(iii) chlorate is a slightly soluble inorganic salt with the formula Cr(ClO3)3. I chose to make some chromium chlorate because I could find almost no information on it and I was curious about what it would be like.

 I knew copper(ii) chlorate was very soluble, so I thought chromium(ii) chlorate would be as well. I tried adding a solution of chromium(ii) sulphate to a solution of calcium chlorate. I hoped that calcium sulphate would precipitate and I would be left with a chromium(ii) chlorate solution. A precipitate did form, but it was a blue-green color so I knew it couldn't be purely calcium sulphate.

I decided to give chromium(ii) chlorate a break and try making chromium(iii) chlorate.

I prepared a chromium(iii) chloride solution and to it I added a solution of calcium chlorate. A navy blue precipitate of chromium(iii) chlorate formed! The same precipitate formed when sodium chlorate was used in place of calcium chlorate. Anyway I filtered off the chromium(iii) chlorate and dried it. Success!












left = dried chromium(iii) chlorate / right = pyrotechnic with chromium(iii) chlorate and Mg
2 CrCl3 + 3 Ca(ClO3)2 ==> 3 CaCl2 + 2 Cr(ClO3)3

2-Benzoxazolinone

2-Benzoxazolinone or 2-(3H)-benzoxazolone is an organic compound used as a precursor to several insecticides. It has quite an interesting structure (in my opinion anyway). I plan to use 2-Benzoxazolinone to make 2-aminophenol.

2-Benzoxazolinone can be made from salicylamide. I tried this out.

To a 225ml conical flask, I added 3.4g of crude salicylamide and 100ml of water. I then placed this in an ice bath to cool down. To a separate vessel, I added 50ml of water, 3g of sodium hydroxide and 13ml 4% sodium hypochlorite bleach. The sodium hydroxide prevents ring chlorination. Anyway, once the salicylamide mixture had cooled to 7 C, I started to slowly add the bleach mix in 5ml portions with strong stirring. It's very important that the temperature is low. Once the bleach addition was complete, I added 15ml 10% sodium hydroxide solution and heated the mixture to 70 C for 30 minutes. After this I chilled the mixture down again in the ice bath.

Once the temperature had fallen to 8 C, I added 25ml of 33% hydrochloric acid. A fluffy brown precipitate of 2-benzoxazolinone formed. I filtered the product off and dried it. I was left with 1.8g of 2-benzoxazolinone which is a 54% yield. Not a bad day's work!

For how the reaction works see this
http://www.sciencemadness.org/talk/files.php?pid=416184&aid=42761

Copper carbonate

Copper carbonate is a nicely colored copper salt used as a pigment. Its formula is often stated to be CuCO3 but Cu3(OH)2(CO3)2 and (Cu2(OH)2CO3) are closer to the truth. I plan to use it to catalyze the decarboxylation of niacin to pyridine, as well as to make calcium copper silicate.

Copper carbonate is relatively easy to make. I made some.

To a 500ml beaker I added 20g of copper sulphate pentahydrate and 150ml of water. The mixture was stirred to give a clear blue solution. With strong stirring, I slowly added 20g of sodium bicarbonate. As I added the sodium bicarbonate, the mixture started foaming and a wonderful green-blue colored precipitate of copper carbonate gradually formed. Once all the sodium bicarbonate had been added, the mixture was filtered to collect the copper carbonate product. After drying, I was left with 31g of copper carbonate.

NaHCO3 + CuSO4 ==> Cu(HCO3)2 + Na2SO4  /  Cu(HCO3)2 ==> CuCO3 + H2O + CO2

Calcium hydroxide

Calcium hydroxide, commonly called slaked lime or caustic lime, is a compound used in cement and to treat sewage. It is slightly soluble in water, and saturated solutions are called limewater. I am interested in using calcium hydroxide as a catalyst for the production of diacetone alcohol.

 Calcium hydroxide can be easily made from sodium hydroxide and calcium chloride. I tried this out.

To a 500ml beaker I added 27g of calcium chloride, then just enough hot water to dissolve it. I set the beaker aside. Then to a 250ml flask I added 20g of sodium hydroxide and a sufficient amount of water to dissolve it. Once the calcium chloride and sodium hydroxide had dissolved into solutions, I added them together. A dense white precipitate of calcium hydroxide formed. I filtered the calcium hydroxide off and dried it in the sun. This yielded 22g of calcium hydroxide in the form of a white powder. The photo was taken before the calcium hydroxide was fully dry.

CaCl2 + 2 NaOH ==> Ca(OH)2 + 2 NaCl