Dr. Andrea Dragon
 |
| Seaweed Saves England |
Each of the hundreds of millions of shells Great Britain fired from thousands of field guns, howitzers and mortars during World War I contained two explosives: cordite, a kind of nitrocellulose (what Americans call smokeless powder) to propel the shell out of the artillery piece and send it flying toward the target, and TNT, the shell’s high explosive payload to blow up the target on impact.
In the early months of the war, the demand for cordite far exceeded the manufacturing capacity of Great Britain’s explosives factories. To meet production demands, in October, 1914, the British Army contacted representatives from DuPont and its 1912 spinoff Hercules, who were the leaders of New Jersey’s established explosives industry, and signed agreements with them to produce nitrocellulose and cordite, load it and TNT into shells, and ship them from New Jersey ports to the Western Front.
But cordite was different from the nitrocellulose-based smokeless powder products New Jersey explosives pioneers had been manufacturing in “powder towns” since the late 19th century. Unlike American smokeless powder, cordite included nitroglycerin transforming it into a “double-base” explosive. Although New Jersey’s powder industry had decades of experience with nitroglycerin (at that time, anything, even a liquid, that exploded was a “powder”), no one had ever added it to smokeless powder because nitroglycerin damaged gun barrels. That’s why the British cordite formula (30% nitroglycerin, 65% nitrocellulose, 0.8% acetone) also included 5% vaseline to coat and shield gun barrels from this kind of damage.
At first, executives of the New Jersey explosives industry believed nothing much stood in the way of them making tons of cordite and tons of money. Not only was manufacturing nitroglycerin in sufficient quantities fairly easily done, vaseline could be sourced from the large Cheeseborough-Ponds factory in Perth Amboy. America’s vast railroad network could transport the cotton needed to make nitrocellulose from southern states to New Jersey’s powder towns. Everything seemed to be in place to start building factories for cordite production, but there was still one very big problem the explosives industry had to solve – where to obtain acetone.
Most readers are familiar with the organic chemical acetone because it’s useful to have around the house not only as a nail polish (which is mostly nitrocellulose) remover but also because there’s nothing better for removing paint or sticky gunk children have spread around. Bought at the local home improvement center, acetone efficiently cleans off lacquer and oily finishes from metal surfaces before repainting. Today, it’s one of the many products produced by the petroleum industry and is inexpensive and ubiquitous, but during WWI acetone was scarce because Germany had been the world’s leading supplier.
It wasn’t as if Great Britain’s early 20th century chemists didn’t know how to make acetone, which was a by-product of burning wood to make charcoal. The basic principles of acetone production had been known since the Middle Ages, weren’t covered by patents, and didn’t require sophisticated technical equipment.
Output estimates vary, but roughly speaking it took a hundred tons of wood to yield just one ton of acetone. When the war began in 1914, most of Great Britain’s forest reserve was long gone, but Germany’s vast Black Forest had ample trees for making acetone and dominating the market.
Since 1862, when Louis Pasteur discovered that alcohol was a product of fermentation by clostridium bacteria, chemists had been experimenting with fermentation to learn how the process produced various alcohol-like substances. One of these chemists, Chaim Weizmann, a Russian immigrant scientist and one of the founders of the modern state of Israel, was researching methods of producing synthetic rubber at the University of Manchester when he discovered that acetone, butanol and ethanol could be created by fermenting starchy grains or potatoes using a type of clostridium bacterium (other, more sinister clostridia bacteria cause botulism and C. difficile) commonly found in soil. Weizmann patented it two years later. This breakthrough meant that instead of clear-cutting and burning up Great Britain’s meager remaining forests, acetone could be produced much more efficiently by fermenting an (easily) renewable crop like corn.
Soon tons of American-grown corn were being shipped to Great Britain to be fermented into acetone, but this process became problematic for three reasons. First, German U-boat activity made trans-Atlantic shipping risky. Second, corn took up precious space in ships that could be used for more high-value cargo. Third, corn was a food crop and during the war many people in Great Britain were hungry, making it hard for the government to justify turning food into an industrial chemical. England was importing 30% of its food consumption from U.S. and Canada. Clearly, other sources of fermentable starch had to be found. For a while, British children were encouraged to gather horse chestnuts, but fermenting them was unsuccessful and the search for ways to make acetone continued.
In 1916, the situation had become so desperate that Prime Minister Lloyd George proposed taking over all distilleries in the United Kingdom and transforming them into acetone factories.
American explosives manufacturers weren’t sure how they would solve the acetone problem. Nevertheless, in February of 1915 Hercules Powder Company signed a contract to produce millions of pounds of cordite at its New Jersey nitrocellulose “powder works.” The contract stipulated that Hercules would have to find an acetone supplier who wasn’t part of any current supply chain to prevent Hercules from either reducing the existing supply of acetone, or from cornering the market. Not only that, to get the cordite contract, Hercules promised to keep track of all the acetone it used and supply Great Britain with an equal amount.
Why was acetone required to make cordite? Why was a solvent needed to make any kind of smokeless powder? At its most basic level, nitrocellulose is simply cotton that has been soaked in nitric acid and then dried until it forms a stiff, white mass. Because ignited nitrocellulose burns first on its surface, forcing a solid mass of nitrocellulose through a large extruding machine not unlike a modern pasta-maker increases its external surface by transforming the single mass into many spaghetti-like strands, or cords. But before that could happen, the stiff lump of nitrocellulose had to be mixed with a solvent to change it into a gelatinous dough pliable enough to go into the hopper of the extruding machine, be forced through the holes, and come out the other end as strands of cordite.
Hercules and other American smokeless powder manufacturers used ether-alcohol as a solvent, but the British specified acetone because cordite made with it required less of the gun barrel-corroding nitroglycerin than powder made with ether-alcohol. At first, Hercules management tried to make acetone from acetic acid bought from manufacturers of table vinegar but weren’t successful. Then the company tried arranging with industrial distillers of wood alcohol to produce acetone, but the process was developing too slowly and didn’t produce the quantities needed to fulfill the cordite contract. Not only was Hercules falling behind the cordite production schedule to the tune of a million pounds a month, it was also woefully short on its promised deliveries of acetone to Great Britain.
Hercules’s management investigated making acetone from beer slop, molasses, and wood pulp without much success. The company’s situation was bleak when George Markell, vice-president and general manager of the company’s New Jersey operations, read in an old encyclopedia that Scots living near the coast once gathered kelp from the ocean, dried and burned it in retort-like ovens recovering potash which they used as a fertilizer. After he learned that acetic acid could be produced by fermenting kelp, Markell developed a plan to harvest kelp from the Pacific Ocean off the coast of Southern California, put it in vats, allow it ferment like beer, capture the acetic acid given off in the fermentation process, and make acetone from the acetic acid.
Markell knew a huge bed of kelp existed a short distance from San Diego and best of all, it was essentially free. Markell went to California in 1915 and began buying up land near Chula Vista, then contracted with a Midwest farm equipment manufacturer to design and build a large hay-mower capable of operating in sea water. Hercules wasn’t the only explosives company seeking to cash in on the skyrocketing demand for acetone so Markell concocted a cover story claiming his company was going to “farm” kelp to make potash fertilizer. Soon 1,500 Hercules employees were using the special mowers to harvest tons of kelp, load it onto barges which transferred it to shore where some of it was used to make potash while the rest was put into two-hundred 50,000-gallon wooden tanks and allowed to ferment producing acetic acid that was further processed yielding not only acetone, but other useful ketones such as methyl-ethyl ketone, a lacquer thinner, as well as potassium nitrate (saltpeter) one of the ingredients of black gunpowder. By the middle of 1917, nearly one million pounds of acetone, produced from 600,000 tons of kelp, had been loaded into railroad tank cars and shipped to New Jersey where 5,000 tough, brave powder men and women working in hazardous conditions made cordite for Great Britain at a rate of 100,000 pounds per day.
After the war, Hercules closed its Chula Vista operation in 1919 and today the site is a nature center.
Recently, I ran across a 2022 scholarly article describing new efforts to produce acetone from kelp harvested off the coast of Scotland. This article ran to forty-two pages, had eleven authors, and contained eighty-five footnotes but not a single word about the Americans who fermented kelp, produced acetone, and made the cordite that helped Great Britain achieve victory in World War I.
Dr. Dragon teaches a course at Rutgers University, New Brunswick, New Jersey on the New Jersey explosives industry.
Related essays by Dr. Dragon:
The Maxim Machine Gun and Smokeless Powder
New Jersey Artillery Explosives Production in World War I
