Boron nitride

Boron nitride is an interesting compound used in ceramics and cosmetics. It's moderately heat resistant and can withstand temperatures up to 2,800 C in the absence of oxygen. Boron nitride occurs in several different forms, which are structurally very similar to the allotropes of carbon. Graphite, diamond and lonsdaleite each have boron nitride analogs.

There are several good ways to make boron nitride. I tried a couple of them out. The reaction of urea with boron trioxide I found to be by far the most reliable, so this is the one I decided to present in this post.

The first step is to convert boric acid to the required boron trioxide.

To a metal can, I added 16g of boric acid. I then strongly heated the can over a camping stove. The boric acid began to melt and give off steam. The mixture became a glassy bubbling syrup as the boric acid was converted to boron trioxide. After about 15 minutes, the bubbling had almost completely stopped and I allowed the mixture to cool. Upon cooling, the boron trioxide solidified into a brittle glass-like substance. I scraped the product out of the can and was left with 8.6g of boron trioxide.

With boron trioxide prepared, I moved on to making the boron nitride.

I ground up the 8.6g of boron trioxide (made above) with 20g of urea. I then poured this mixture into a metal can, which I heated over a camping stove for 30 minutes with gradually increasing heat and fairly constant stirring. The mixture formed a bubbling melt, which diminished after a few minutes to a solid mixture. If the heat is increased too rapidly, a significant amount of boron trioxide can fail to react. I made this mistake, so after the 30 minutes of heating, I added an additional 10g of urea and continued heating for 10 minutes. This probably wouldn't have been necessary had I not started heating so strongly at the beginning.

Anyway after this, I allowed the mixture to cool to room temperature. I then crushed the mixture up and added it to a 150ml beaker containing 75ml of dilute hydrochloric acid. I left this to soak overnight. The next morning most of the white boron nitride had settled to the bottom of the beaker. Above it there was a thin layer of brown material. I stirred the mixture up, waited until the most of the boron nitride had settled, then carefully decanted and discarded as much of the supernatant liquid-brown material suspension as I could. I then washed the residual boron nitride with 100ml of cold water. I filtered off the boron nitride, washed it on the filter with 20ml of ethanol, then dried it. I was left with 2.15g of white boron nitride which is a 35% yield.

The procedure I was following (here) called for boiling the product in water to purify it. However I've found in previous runs that this tends to completely destroy the product. It's well known that hot water reacts with boron nitride, so I'm not sure why they suggest this method of purification.

2 B(OH)3 ==> B2O3 + 3 H2O    /   B2O3 + (NH2)2CO ==> 2 BN + 2 H2O + CO2

B2O3 + 3 C2H5OH ==> (C2H5)3BO3 + B(OH)3

Myristic acid synthesis

Myristic acid, or tetradecanoic acid, is a fatty acid with very few common uses. It is however, a useful organic building block. Under standard conditions, myristic acid is a low melting white crystalline solid. I'm not sure if I'll use my myristic acid for anything, although maybe I'll make some myristyl alcohol or a myristate ester.

Myristic acid can be made by the alkaline hydrolysis of trimyristin. This is a fairly easy and straightforward synthesis.

To a 500ml round-bottom flask, I added 1.43g of trimyristin and a solution of 11.43g sodium hydroxide in 48ml of water. I then added in 45ml of ethanol and attached a Liebig condenser to the flask. I refluxed the mixture for 1 hour and 30 minutes on a medium heat, adding in an additional 10ml of ethanol after the first 45 minutes. The trimyristin dissolved quickly and the liquid turned red, but after this, there wasn't much visible change. Once the reflux was complete, I let everything cool to room temperature. I then poured the mixture into a 200ml conical flask. At this point, the mixture consists of mostly sodium myristate dissolved in water. To get the myristic acid, the sodium myristate must be acidified with a strong acid. So I added 27ml of 33% hydrochloric acid. The red colour lightened to a yellow and the mixture became cloudy. I did add in a little bit more hydrochloric acid by accident, which was completely unnecessary.

Anyway, after a few minutes, a white precipitate of myristic acid began to collect on the bottom of the flask. I chilled the mixture down to get as much myristic acid to crystallize out as possible. A bit of unreacted trimyristin floated on top of the liquid and this was carefully decanted off. I then filtered off the myristic acid, washed it with 50ml of water, then dried it. I got 0.36g of myristic acid, which is a 27% yield.

I'm honestly not sure why the yield was so low.

(C13H27COO)3C3H8 + 3 NaOH ==> 3 NaC13H27COO + C3H8(OH)3

NaC13H27COO + HCl ==> C13H27COOH + NaCl

Oxidation of toluene to benzoic acid

Benzoic acid is an aromatic carboxylic acid used as an organic building block. It occurs naturally in a wide range of plants, and is used as a food preservative. It's also an ingredient in many cosmetics. I plan to use benzoic acid to synthesize Benzamide and eventually aniline.

Benzoic acid can be made very easily from toluene. I did a test run to see if I could get this to work.

To a 250ml beaker I added 15g of potassium permanganate and 157ml of water. With a bit of stirring, most of the potassium permanganate dissolved giving a dark purple solution. I then added this solution (and the small amount of undissolved potassium permanganate) to a 500ml round-bottom flask. Next I added 35ml of technical grade toluene and attached a liebig condenser to the flask. I then strongly refluxed the mixture for 2.8 hours. The mixture gradually darkened as the potassium permanganate was converted to brown manganese dioxide. After 2.8 hours of reflux, I allowed the mixture to cool to room temperature. The purple colour of permanganate had completely gone, indicating all potassium permanganate had been consumed. I filtered the mixture to remove the manganese dioxide by-product. Manganese dioxide is a useful chemical to have, so I kept mine rather then discarding it.

 Anyway, I transferred the clear filtrate to a 250ml beaker, a small layer of excess toluene floated on top of the surrounding liquid. I removed the toluene with a syringe and saved it for future runs. After this, I was left with about 125ml of liquid in the beaker. This is a solution of potassium benzoate in water. I slowly added 33% hydrochloric acid to the solution and fluffy white crystals of benzoic acid precipitated. I kept adding hydrochloric acid until no more precipitate formed.

I then filtered off the benzoic acid and dried it. I got 2.45g of benzoic acid as fine fluffy white crystals.

The reason for the small amount of product obtained was my scales which were broken and gave a false reading.
Due to this I actually used a lot less than 15g of permanganate. I have no idea how much permanaganate I used so I can't calculate the real yield.

2 KMnO4 + C6H5CH3 ==> KC6H5COO + 2 MnO2 + KOH + H2O

KC6H5COO + HCl ==> C6H5COOH + KCl

Trimyristin from nutmeg

Trimyristin, or glyceryl trimyristate, is an interesting triglyceride that occurs naturally in nutmeg. It doesn't have many uses except in scientific research. Trimyristin can be hydrolysed to glycerol and myristic acid, and in the future I plan to try this out. Ground dry nutmeg typically contains about 25% trimyristin (by weight) so this is a great source of the compound.

The extraction of trimyristin from nutmeg is a classic experiment. Usually diethyl ether is used as the extraction solvent, but I tried using a different method.

To a 250ml conical flask, I added 40g of dry ground nutmeg. To this I added 100ml of hot (nearly boiling) ethanol and stirred vigorously for 15 seconds. I then immediately filtered the mixture through a cloth, collecting the orange filtrate in a 200ml conical flask. I washed the nutmeg on the filter with 25ml more hot ethanol. It's important that the whole filtering process is performed quickly while the ethanol is still hot, otherwise the trimyristin will start crystallizing out. Anyway, the 200ml conical flask containing the filtrate (already starting to precipitate some product) was chilled to about 2 C. A lot more trimyristin crystallized out and the mixture was filtered to collect it.

After filtration, I was left with fine crystals of almost white trimyristin. I decided to perform a recrystallization from ethanol to purify my product. After recrystallization, I was left with 0.84g of trimyristin as very fine white crystals. The product was easily melted by hot water, which is a good sign as trimyristin is said to melt at about 56 C. My guess is the trimyristin isn't extremely pure but still definitely usable for most things.

Left = recrystallized trimyristin   Right = ground nutmeg

This extraction was poorly planned and performed. I probably could have gotten more product by boiling the nutmeg in ethanol at the start. My procedure was loosely based on this.

Ammonoylsis of diethyl oxalate to oxalamide

Oxalamide or ethanediamide, is an organic compound used as a fertilizer. It's also used as an additive in some rocket fuel mixtures to help slow the burning rate. At room tempurature, oxalamide exists as a white solid. When heated past 350 C, it decomposes releasing deadly cyanogen gas. I did plan to use oxalamide for an experimental synthesis of cyanoformamide, but I decided that this was too dangerous.

Oxalamide can be made by the ammonoylsis of diethyl oxalate. This is a quick and very easy synthesis.

First I added 24ml of 25% aqueous ammonia solution to a 100ml beaker. Then using a syringe, I added 10ml of diethyl oxalate. At first the diethyl oxalate just formed a bottom layer, but after a few seconds, I noticed a white precipitate (presumably oxalamide) beginning to form. I began stirring the mixture and rapidly more oxalamide precipitated. The mixture got thicker as the precipitate built up. After about 1 minute of stirring, the mixture had become a thick white paste. Once this point was reached, I transferred the pasty mixture on to a sheet of paper to dry. After drying, I was left with 6.42g of a white powder, which is almost definitely oxalamide. If pure, this represents a 99% yield!

 A nice feature of the reaction is that oxalamide is the only non-volatile solid involved. This means a fairy pure product can (in theory) be obtained just by allowing the mixture to dry. The only thing that could contaminate the product is unreacted diethyl oxalate. For this reason, I used a 10% excess of ammonia solution to ensure all the diethyl oxalate reacted.


(C2H5)2C2O4 + 2 NH3 ==> (CONH2)2 + 2 C2H5OH

Diethyl oxalate

Diethyl oxalate, or diethyl ethanedioate, is a interesting ester used as an organic building block. It has an ethereal smell similar to grape juice. Diethyl oxalate is also used as a specialty solvent for various resins, and as a pigment carrier. In the pharmaceutical industry, diethyl oxalate is used to produce barbiturate steroids. I plan to use it to prepare ethyl acetopyruvate and oxalamide. Diethyl oxalate can be made from dry ethanol and anhydrous oxalic acid. I tried this out.

To get a good yield, the hydrated oxalic acid used must be made anhydrous.

To a large crystallizing dish, I added 100g of oxalic acid dihydrate. I then placed the crystallizing dish
on a hotplate and lowered in an overhead thermometer. I heated the oxalic acid at around 140 C until no more water boiled off. During this process, the oxalic acid melted and a large amount of vapor
(mostly steam) was boiled off. This is not a very effective way to produce anhydrous oxalic acid, but I got there in the end.

To a 500ml round-bottom flask, I added the anhydrous oxalic acid prepared above. I then added 200ml of ethanol and a drop of 98% sulphuric acid, then set up for reflux. I allowed the mixture to reflux for 2 hours. The anhydrous oxalic acid dissolved but apart from this, there was not much visible change in the mixture. After 2 hours of reflux, I removed the condenser and set up for simple distillation. The first fraction came over at 71-81 C,  consisting of ethanol/water azeotrope. About 175ml of this was collected. The temperature of the distillate then rose to 100 C, and I changed the receiving vessel. I kept collecting distillate until nothing was left in the distilling flask. The temperature had climbed to 220 C at the end of the distillation. I had collected 50ml of clear liquid, predominantly diethyl oxalate.

To this liquid, I added 60ml of saturated sodium chloride solution. I shook the mixture up then let it settle. The diethyl oxalate separated, forming a layer above the surrounding liquid. I collected the diethyl oxalate product with a syringe, dried it over anhydrous calcium chloride and finally transferred it to an amber glass bottle for storage. I got 42ml of diethyl oxalate which is a 34% yield.


Adding a drop of sulphuric acid isn't absolutely required as oxalic acid is a strong enough acid to catalyse the reaction.

H2C2O4 + 2 C2H5OH ==(- H2O)==> (C2H5)2C2O4 + 2 H2O

2-Aminophenol via hydrolysis

2-Aminophenol, or 2-hydroxyaniline, is an organic compound used in photography. It's a valuable reagent used to synthesize many heterocyclic compounds such as benzoxazoles (many of which are important in the pharmaceutical industry). I plan to use 2-aminophenol to synthesize catechol. Although I'm not sure if I'll ever get around to it.

2-Aminophenol is formed via the acid hydrolysis of 2-benzoxazolinone. I tried this out.

To a 500ml round bottom flask, I added 27ml of 33% hydrochloric acid and 70ml of water. I then added 1.8g of 2-benzoxazolinone and set up for reflux. Using a boiling water bath as the heating source, I gently refluxed the mixture for 2 hours. The 2-benzoxazolinone gradually dissolved leaving a clear brown-yellow solution. After the reflux, I allowed the mixture to cool down to room temperature. As the mixture cooled, fluffy white crystals of 2-aminophenol began to precipitate.

Once the mixture had fully cooled, I filtered off the 2-aminophenol product. After drying I was left with 0.62g of slightly brown 2-aminophenol which is a 42.6% yield.

A note on safety: although the deadly gas phosgene is produced in this reaction, it immediately reacts with the water present as soon as it is formed. Due to this, the risk of phosgene poisoning is extremely low.


C6H4(O)NHCO + 2 HCl ==> C6H4(OH)NH2 + COCl2  /  COCl2 + H2O ==> CO2 + 2 HCl