Phosphate Rocks References

Culture
7th May 2024

Article by Staff Writer

People

i. Jabir ibn Hayyan (721–815)

The father of chemistry, Jabir was an eighth-century natural philosopher and experimental chemist who lived in Persia and Iraq. He wrote many books in Arabic, providing the first systematic classification of chemical substances and documenting the oldest known instructions for making inorganic chemical compounds (such as ammonium chloride) from living things. His Latinised name (Geber) may also be the origin of the word gibberish (incomprehensible technical jargon) as his work was written in highly esoteric code to ensure that only those who had been initiated into his alchemical school could understand it.

ii. Katherine Jones, Lady Ranelagh (1615–1691)

Katherine was the seventh of fifteen children. She was betrothed at nine, married at fifteen and bore four children before escaping from war in Ireland and an unhappy marriage to set up an independent life in London. Together with little brother Robert Boyle, she embarked on ‘a lifelong intellectual partnership, where brother and sister shared medical remedies, promoted each other’s scientific ideas, and edited each other’s manuscript’. They made a wish list of twenty-four inventions including the ‘art of flying’, ‘perpetual light’, ‘making armour light and extremely hard’, ‘a ship to sail with all winds’ without sinking, ‘practicable and certain way of finding longitudes’, ‘potent drugs to… appease pain’⁴⁰.

iii. Robert Boyle (1627–1691)

Robert was a seventeenth-century chemist, born into a wealthy family and free to pursue scientific interests. The fourteenth of fifteen children, he never married but formed an intellectual partnership with his brilliant older sister, Katherine Jones. He visited Galileo Galilei in Italy in 1641 to gaze at stars and ponder the paradoxes of the universe. He hired brilliant polymath Robert Hooke (1634–1703) as his laboratory assistant and contributed to the founding of the Royal Society in 1662. One of the pioneers of the modern experimental scientific method, he proved that the absolute pressure of a gas is inversely proportional to its volume (Boyle’s Law).

iv. Hennig Brand (1630–1710)

The last of the alchemists, Henning discovered the chemical element phosphorus in 1669 while searching for the ‘philosopher’s stone’, a catalyst to turn base metals into gold. He married twice.

v. John Roebuck of Kinneil (1718–1794)

John was an inventor and industrialist who developed a process for industrial-scale manufacture of sulphuric acid using rectangular wooden chambers lined with lead. He trained as a medical doctor in Edinburgh and Leiden, but his passion was for chemistry.

vi. Antoine Lavoisier (1743–1794)

Antoine was a French nobleman, tax collector and scientist. He proved the role played by oxygen in combustion and changed chemistry from a qualitative (descriptive) to quantitative science with his passions for accurate measurement. He worked for the private tax-collecting arm of the French government (Ferme Générale) as gunpowder administrator, where his interest in chemistry blossomed and he was able to construct a state-of-the-art chemistry laboratory. He married Marie-Anne Pierrette Paulze and his wife assisted with his scientific research, translating scientific papers and actively participating in her husband’s laboratory work. At the height of the Reign of Terror during the French Revolution, he was accused of tax fraud, convicted and executed by guillotine. He was later completely exonerated.

vii. Marie-Anne Pierrette Paulze (1758–1836)

Marie-Anne was three years old when she was sent to a convent on the death of her mother. Married at the age of thirteen to Antoine Lavoisier (then aged twenty-eight) to avoid a union with a much older man at her father’s workplace, the Ferme Générale, Marie-Anne became her husband’s lab assistant, translator and illustrator. Her husband and father fell afoul of the French Revolution and were both executed by guillotine on the same day in 1794. She remarried in 1804, to the American-born physicist Sir Benjamin Thompson, Count Rumford, but the second marriage was not a happy one and they separated after three years.

viii. Alexander von Humboldt (1769–1859)

The first person to identify human-induced climate change, Alexander was a Prussian explorer, botanist and geographer who travelled the world and published thirty volumes of beautifully illustrated observations. Together with his friend Joseph Louis Gay-Lussac, he made water from hydrogen and oxygen. He never married.

ix. Jane Marcet (née Haldimand) (1769–1858)

Jane wrote and illustrated popular science books, ‘Conversations’, that were both accessible and scientifically accurate. One of twelve children born to a Swiss banker in London, she was educated with her brothers and took over the running of the household and her father’s scientific and literary soirées from the age of fifteen when her mother died. She published Conversations on Chemistry anonymously in 1803. It was based on Humphry Davy’s public lectures and was to have a profound effect on Michael Faraday. She married a doctor and they set up a chemical laboratory at their home in London. She had four children.

x. Humphry Davy (1778–1829)

Humphry was a British chemist and the father of electrochemistry. He perfected a safety lamp for Cornish miners and identified several chemical elements: potassium, sodium, calcium, strontium, barium, magnesium, and chlorine. He was a brilliant scientific communicator, appointed as a chemistry lecturer to the newly created Royal Institution at the age of twenty-two. An incorrigible experimenter, he took enormous personal risk. Almost asphyxiating himself with nitrous oxide (which he named laughing gas), he became temporarily blind while preparing nitrogen trichloride, but it didn’t teach him any lessons about safety. His laboratory assistant, Michael Faraday, took over preparation and both suffered another accident when the explosive… exploded. He was a supporter of women’s education, married once and had no children.

xi. Joseph Louis Gay-Lussac (1778–1850)

Amateur balloonist Joseph was a French scientist with professorships in both chemistry and physics. He improved the design of lead chambers for the manufacture of sulphuric acid by adding packing and cooling. He proved that gas pressure increases with temperature, discovered the chemical elements boron and iodine, developed pipettes and burettes and carried out many experiments with alcohol and water to develop the ‘degrees Gay-Lussac’ scale. It’s a tough job, but someone has to do it. He married once and had five children.

xii. Peregrine Phillips (1800–1888)

Peregrine was a vinegar merchant who improved the manufacture of sulphuric acid with the invention of the new contact process.

xiii. Michael Faraday (1791–1867)

Michael discovered and applied the underlying principles of electromagnetism and electrolysis and founded the Royal Society Christmas Lectures in 1825. The son of a blacksmith, he received almost no formal education and never developed his mathematical abilities beyond basic algebra and trigonometry. Despite these humble beginnings, Michael became one of the most influential scientists in history, laying the groundwork for James Clerk Maxwell, Albert Einstein and Ernest Rutherford. While apprenticed to a bookbinder he read the popular science books of Jane Marcet and became fascinated with science. He approached Davy and was taken on as an assistant. Eschewing worldly ambition and material riches, he turned down the offer of a knighthood and would not stand as president of the Royal Institution. He refused to advise the British Government on the production of chemical weapons for the Crimean War on ethical grounds. He married once and had no children.

xiv. Amelia Joule, née Grimes (1814–1854)

I wish I knew more about Amelia. History only records that she was the daughter of the Liverpool Comptroller of Customs and, aged thirty-three, married James Prescott Joule. They had three children. She died aged forty, along with her youngest child, shortly after giving birth. Life was pretty rubbish for Victorian women and infants.

xv. James Prescott Joule (1818–1889)

James Prescott Joule was a British scientist who discovered the relationship between heat and work which led to the first law of thermodynamics and the principle of conservation of energy. Joule’s gravestone is inscribed with the number 772.55, the mechanical equivalent of heat. In 1878 he showed by experiment that the same amount of energy is required to lift 772.5 pounds weight by one foot as is required to heat one pound of water by one degree Fahrenheit. In other words, the amount of mechanical work necessary to raise the temperature of one kilogram of water by one degree Celsius is the same as it takes to lift 427 kilograms by one metre. He famously invited Lord Kelvin on his honeymoon after marrying Amelia Grimes. James and Amelia had three children.

xvi. William Thomson, 1st Baron Kelvin, (1824–1907)

The first British scientist to be elevated to the House of Lords, William was a physicist and telegraph engineer who helped to formulate the first and second laws of thermodynamics and unified physics as we know it today. He joined James Prescott Joule and his new wife Amelia on honeymoon. He married twice. After his first wife died, he bought a schooner, Lalla Rookh, and took to the sea. He proposed to his second wife by telegraph as he approached Funchal harbour in Madeira. Fortunately, she was proficient in morse code, and accepted.

xvii. Carl Friedrich Claus (1827–1900)

Carl was a German-born British chemist. He invented a process to recover high purity sulphur from hydrogen sulphide gas. He married twice and had five children.

xviii. Herman Frasch (1851–1914)

Herman was a German-born American chemist and mining engineer. He invented a process for fractional distillation of crude oil with the removal of sulphur. In the process named after him (Frasch process), he used superheated water to melt sulphur deposits underground and bring it to the surface as liquid. He married twice and had two children.

xix. Wilhelm Ostwald (1853–1932)

Wilhelm was a Latvian-born German chemist and philosopher who invented a commercial process for making nitric acid. He also made key contributions to the understanding of chemical equilibria (how far), kinetics (how fast), catalysis, crystallisation, atomic theory and Esperanto. He married and had five children.

xx. Booker Taliaferro Washington (1856–1915)

Booker T. was an African American born into slavery. He was freed from a plantation aged nine and worked in salt furnaces and coal mines, teaching himself to read and write and progressing to a black college, going on to lead a university. He visited Europe, including the sulphur mines of Sicily in 1910. He became the leading voice of former slaves and their descendants, championing black progress through education and entrepreneurship. He married three times and had three children.

xxi. Fritz Haber (1868–1934)

The inventor of a process to fix nitrogen and ‘make bread from air’, Fritz also led a team perfecting the manufacture and deployment of chemical weapons. He married Clara Immerwahr and they had one son, Hermann, who at the age of twelve witnessed his mother’s slow death from a self-inflicted gun injury (Hermann later died by suicide himself). Fritz married again and had two further children, but the marriage broke up. He escaped from Nazi Germany in 1933 but was not readily accepted outside Germany and died in Switzerland, impoverished and alone.

xxii. Clara Immerwahr (1870–1915)

Clara Immerwahr was a German chemist, the first German woman to be awarded a doctorate in chemistry. She married Fritz Haber in 1901 but shot herself in 1915 in protest at his work with chemical weapons. She had one child.

xxiii. Carl Bosch (1874–1940)

Carl was a German chemical engineer. As an employee of BASF, he was responsible for scaling up Fritz Haber’s process to obtain full-scale manufacture of ammonia. This involved finding the right catalyst, designing materials and equipment that could withstand the high pressures and temperatures and purifying the feedstock (hydrogen and nitrogen) and the product ammonia. He married once and had two children.

xxiv. Robert Le Rossignol (1884–1976)

Robert Le Rossignol was a British chemist who worked with Fritz Haber on the Haber-Bosch process. He was interned in Germany in 1914 at the outbreak of the First World War, returning to Britain at the end of the war. He married and had two children, both of whom he outlived.

xxv. Dan Flavin (1933–1996)

Dan Flavin was an American minimalist artist who created installations using coloured fluorescent light. He designed the artworks for specific gallery spaces, creating bespoke light and shade. ‘monument’ for V. Tatlin was an exhibition in homage to Vladimir Tatlin, a Russian sculptor: ‘the great revolutionary, who dreamed of art as science’. In order to preserve twentieth-century artworks, curators and conservators have to make decisions about authenticity and obsolescence, artistic intent and interpretation. The original, energy-inefficient fluorescent tubes are no longer made. Modern conservationists must make difficult decisions about how to maintain the works.

Or not.

Processes

A. Claus Process (1893) – Manufacture of sulphur

Hydrogen sulphide gas reacts with oxygen to give solid sulphur and water.

2 H₂S _(gas) + O₂ _(gas) → S_{2 (solid)} + 2 H₂O _(liquid)

A1. First step – Hydrodesulphurisation of oil

Organo-sulphur compounds (found in coal, oil and gas) react with hydrogen to give hydrogen sulphide gas, for example with ethanethiol.

C₂H₅SH + H₂→ C₂H₆+H₂S

A2. Second step – Burn in restricted air

Hydrogen sulphide gas is fed to a furnace and burnt with a restricted amount of air so that only one third is oxidised to sulphur dioxide.

2 H₂S +3 O₂ →2 SO₂+ 2 H₂O

A3. Third Step – Catalytic reduction

The sulphur dioxide and hydrogen sulphide continue over a catalyst bed of titanium dioxide or activated alumina and react to form sulphur, which is condensed and removed as a liquid, then solidified.

4 H₂S +2 SO₂ →3 S₂ + 4 H₂O

B. Contact Process (1831) – Manufacture of sulphuric acid

Solid sulphur is burned in air and dissolved in water to give sulphuric acid.

2 S _(solid) + O₂ _(gas) + 2 H₂O _(liquid) → 2 H₂SO₄ _(liquid)

But, as ever, I think you’ll find it’s a little more complicated than that…

B1. First step – sulphur to sulphur dioxide

Solid sulphur is melted and burned to produce sulphur dioxide gas.

S _(solid) + O_{2 (gas)} → SO_{2 (gas)}

B2. Second step – sulphur dioxide to sulphur trioxide

Sulphur dioxide gas is oxidised to sulphur trioxide over a solid vanadium pentoxide catalyst.

2 SO_{2 (gas)} + O_{2 (gas)} →2 SO_{3 (gas)} (in presence of V₂O₅)

B3. Third step – sulphur trioxide to oleum

Sulphur trioxide is dissolved in concentrated sulphuric acid to form oleum.

H₂SO₄ _(liquid)+ SO_{3 (gas)} → H₂S₂O_{7 (liquid)}

B4. Fourth step – oleum plus water to sulphuric acid

Oleum is diluted with water to form sulphuric acid.

H₂S₂O₇ _(liquid)+ H₂O _(liquid) → 2 H₂SO₄ _(liquid)

C. Manufacture of phosphoric acid

Phosphoric acid is made by reacting phosphate rock with a strong acid. Hydrogen from sulphuric acid H₂SO₄ swaps places with calcium in the rock giving solid calcium sulphate called gypsum– and liquid phosphoric acid. A filter then separates the solids from the liquid.

C1. Wet process

Phosphate rock (fluorapatite (3Ca₃(PO₄)₂.CaF₂)) containing calcium hydroxyapatite and calcium carbonate is mixed with sulphuric acid to give phosphoric acid, gypsum and water.

Ca₃(PO₄)₂ _(s)+ 3 H₂SO₄ _(aq) → 2 H₃PO_{4 (aq)} + 3 CaSO₄ _(s)

CaCO_{3 (s)}+ H₂SO_{4 (aq)} → CaSO_{4 (s)} + H₂O _(l) + CO_{2 (g)}

Side reactions with Calcium fluoride give Hexafluorosilicic acid.

3 CaF_{2 (s)} + SiO_{2 (s)} + 3 H₂SO_{4 (l)}→ H₂SiF_{6 (l)} + 3 CaSO_{4 (s)}+ 2 H₂O _(l)

The reaction conditions determine the crystal structure of the gypsum, which in turn determines the ease of filtration. Gypsum crystals come in the form dihydrate CaSO₄.2H₂O, α-hemihydrate CaSO₄.1/2H₂O or anhydrite CaSO₄. Lower temperatures favour the dihydrate but at higher temperatures the hemihydrate is produced.

The gypsum is removed by filtration and the acid is concentrated using vacuum distillation.

D. Haber-Bosch Process – Ammonia

The revolutionary process that allows humans to fix nitrogen in air was the brainchild of Fritz Haber and Karl Bosch^(xxiii).

N_{2 (gas)} + 3 H_{2 (gas)} → 2 NH_{3 (liquid)}

D1. First step – Nitrogen production

To separate nitrogen from air, you first filter the air to remove dust, and then cool it in stages until it reaches -200°C. As the air cools, the water vapour condenses, and you remove it using absorbent filters. Carbon dioxide freezes at -79°C and you remove it as a solid. Oxygen and nitrogen liquefy between minus 183°C and -196°C. You recover the nitrogen from the liquid air mixture by fractional distillation. Different substances have different boiling points and you choose the number of distillation plates (boiling and condensing stages) to get the purity required.

D2. Second step – Hydrogen production

Hydrogen can be made by splitting water using electrolysis.

2 H₂O → O₂+ 2 H₂

But for economic reasons,most hydrogen is made from natural gas (methane) and steam.

CH₄ + 2 H₂O → CO₂ + 4 H₂

There are several sub-steps:

D2.1. Desulphurisation

Natural gas comes from plants, and plants (and the bacteria which help break them down) contain sulphur, so part of the product hydrogen must be recycled to the start of the process in order to hydrogenate the sulphur-containing organic compounds.

H_{2 (gas)} +RSH → RH + H₂S_(gas)

Where R is an organic group like C₂H₅

The hydrogen sulphide produced is passed through beds of zinc oxide where it is converted to solid zinc sulphide.

H₂S + ZnO → ZnS + H₂O

Or using the Claus process, recovered as solid sulphur.

2 H₂S +3 O₂ → 2 SO₂ + 2 H₂O

4 H₂S +2 SO₂ → 3 S₂ + 4 H₂O

D2.2. Steam reforming

The sulphur-free methane is mixed with high-pressure steam and passed over a bed of nickel catalyst to produce syngas (hydrogen plus carbon monoxide). This step is called steam reforming.

CH₄ + H₂O → CO + 3 H₂

The steam reforming reaction is endothermic – heat is required – so some of the methane feedstock has to be burnt to provide the energy input, increasing speed of reaction and conversion.

D2.3. Water-gas shift

The next step, the water-gas shift reaction, is exothermic – heat is given out. That means higher temperatures drive a faster reaction, but incomplete conversion. The overall water-gas shift reaction converts the carbon monoxide to carbon dioxide and more hydrogen.

CO + H₂O →CO₂+ H₂

In order to take advantage of both the thermodynamics (conversion) and the kinetics (speed) of the reaction, industrial-scale water-gas shift reactions are conducted in multiple stages consisting of a high temperature shift (HTS) followed by a low temperature shift (LTS) with intermediate cooling.

D2.3.1. High temperature shift

The first (HTS) stage takes place over an iron oxide–chromium oxide catalyst. The reaction is fast but results in incomplete conversion of carbon monoxide. To increase hydrogen production, the gases exiting the high-temperature reactor are cooled and fed to the second lower temperature (LTS) stage.

D2.3.2. Low temperature shift

The LTS catalyst is copper-based and extremely sensitive to sulphur, so as well as cooling, the gases pass through a guard bed of metal oxides to trap any cheeky little elfin wisps of sulphur that snuck past earlier.

D2.3.3. Heat exchange

The heat removed between the high temperature and low temperature reactors, along with the energy in the gases leaving the process, is used to heat the incoming feedstock.

D2.4. Carbon dioxide removal

The carbon dioxide is separated from the hydrogen by bubbling it through an amine solution (like MEA = monoethanolamine C₂H₇NO) or by pressure swing absorption where the cooled gases pass through beds of absorbent materials which preferentially mop them up. Once the absorption bed is exhausted, the pressure is reduced and the carbon dioxide is released.

D2.5. Catalytic methanation

Hydrogen is used to remove any leftover traces of carbon monoxide or carbon dioxide and protect the ammonia catalyst.

CO + 3 H₂ → CH₄ + H₂O

CO₂ + 4 H₂ → CH₄ +2 H₂O

D3. React nitrogen and hydrogen of the correct purity to make ammonia

The Haber-Bosch process forward reaction

3 H₂ + N₂→ 2 NH₃

is in equilibrium with the reverse reaction

2 NH₃ → 3 H₂ + N₂

It needs special process conditions to drive the forward reaction at acceptable speed and yield. And a catalyst (which you prepared earlier…)

D4. Magnetite catalyst

Don’t you hate recipes where you chop the onions and fry them with the ground spices and then you turn the page and it says ‘now take the meat that you have previously marinated for 24 hours…’? Maybe I should have mentioned the catalyst first. Just checking to see if you’re still paying attention!

The catalyst for the Haber-Bosch process consists of finely ground particles: each particle has a core of magnetite (Fe₃O₄), encased in a shell of wüstite (FeO), which in turn is surrounded by an outer shell of iron metal (Fe). Tremendous skill in preparation leads to a highly porous high-surface-area catalyst. One of Carl Bosch’s assistants ran over 20,000 experiments to find the perfect catalyst. He discovered that a commonly available iron ore called magnetite could be used to create a catalyst that worked every bit as well as the expensive (and unstable) osmium-uranium catalyst proposed by Fritz Haber in his original patent. The catalyst is key to the process, and yet Alwin Mittasch (1869–1953) rarely gets a mention.

E. Ostwald Process – Nitric acid

Wilhelm Ostwald^(xix) gave his name to the Ostwald process.

E1. First step

Ammonia plus oxygen gives nitric oxide and water.

4 NH₃ (g) + 5 O₂ (g) → 4 NO (g) + 6 H₂O (l)

E2. Second step

The nitric oxide is reacted with air to form nitrogen dioxide.

2 NO (g) + O₂(g) → 2 NO₂ (g)

E3. Third step

The nitrogen dioxide is bubbled through water to form nitric acid and nitric oxide.

3 NO₂ (g) + H₂O (l) → 2 HNO₃ (aq) + NO (g)

The extra nitric oxide is sent back to step E2.

F. Ammonium nitrate

First take ammonia (Haber-Bosch process) and add concentrated nitric acid (from the Ostwald process). Add together and stand well back.

HNO₃ _(aq) (+H₂O) + NH₃ _(g) → NH₄NO₃ _(s) (+H₂O)

Like many reactions of acids (nitric acid) and alkalis (ammonia) to make a salt (ammonium nitrate), this is a violently exothermic reaction, which means a lot of heat is generated. This heat can be used to evaporate the incoming liquid ammonia and heat the salt solution (~80% ammonium nitrate in water), evaporating the residual water to obtain an ammonium nitrate melt (>95% ammonium nitrate). The melt is pumped through a shower head at the top of a spray tower. The melt cools and solidifies in air to make ‘prills’ or small beads. The prills are dried, cooled, and coated to stop them sticking together.

Chemistry, Calculations, Units and Quotes

Chemical elements in the human body - Assuming an average body weight of 70 kg and 0.3% sulphur, the weight of sulphur in the human body is 210 g. Most phosphorus (P, molecular weight 31) is found in the body in the form of hydroxyapatite (Ca₁₀ (PO₄)₆ (OH)₂, molecular weight 1005). Assuming the body has 1% elemental phosphorus or 700 g then there will be (1005/(6 x 31) x 700 = 3782 grams) 3.782 kg of hydroxyapatite. Assuming 0.4% potassium, the weight of potassium in the human body is 280 g. Oxygen (O) 65.0% = 45,500 g - Carbon (C) 18.5% = 12,950 g - Hydrogen (H) 9.5% = 6,650 g - Nitrogen (N) 3.2% = 2,240 g - Calcium (Ca) 1.5% = 1,050 g, Phosphorus (P) 1.0% = 700 g - Potassium (K) 0.4% = 280 g - Sulphur (S) 0.3% = 210 g - All other elements combined 0.6% = 420 g
Pyrites – iron sulphide, FeS
Cinnabar – mercury sulphide, HgS
Galena – lead sulphide, PbS
Stibnite – antimony sulphide, Sb₂S₃
Sphalerite – zinc sulphide, (Zn, Fe)S
Gypsum – calcium sulphate, CaSO₄.2H₂O
Alunite – potassium aluminium sulphate, KAl₃(SO₄)₂(OH)₆
Barite – barium sulphate, BaSO₄
Sicilian Sulphur Mines - Conditions in the mines of Sicily shocked even those used to the brutal treatment of working men. Phillip Carroll, U.S Consul, Palermo, ‘United States Consular Reports. Special Issue No. 10,’ accessed May 20 2020, http://lateralscience.blogspot.com/2018/04/sulphur-mines-in-sicily-1888.html
Washington & Park, The Man Farthest Down.
Hydroxyapatite – Calcium phosphate – Ca₅(PO₄)₃OH, (Ca₁₀ (PO₄)₆ (OH)₂)
Fluorapatite – Calcium fluorophosphate – Ca₅(PO₄)₃F
DNA – Deoxyribonucleic acid
RNA – Ribonucleic acid
ATP – Adenosine tri-phosphate – C₁₀H₁₆N₅O₁₃P₃
ADP – Adenosine di-phosphate – C₁₀H₁₅N₅O₁₀P₂
Rubisco is Ribulose -1,5-bisphosphate carboxylase/oxygenase
Carbon fixation – plants convert carbon dioxide in the air and water in the ground into sugars using energy from sunlight. The first major step is carboxylation of ribulose-1,5-bisphosphate
Guano Islands Act, USA, 1856
President Franklin D. Roosevelt, message to Congress, 1938. https://www.presidency.ucsb.edu/documents/message-congress-phosphates-for-soil-fertility
Chitin – C₈H₁₃O₅N
Mercaptans and Thiols - The term mercaptan comes from the Latin mercurium captāns (capturing mercury) because the thiolate group (RS−) bonds very strongly with mercury compounds. Thiols are the sulphur analogue of alcohols where sulphur takes the place of oxygen in the hydroxyl group. The word is a portmanteau of ‘thio-’ + ‘alcohol’, with the first word deriving from Greek θεῖον (theion) meaning ‘sulphur’.
Furfuryl mercaptan – C₅H₆OS
Grapefruit mercaptan– C₁₀H₁₈S
Tertiary butyl mercaptan – (CH₃)₃CSH
Potassium compounds in potash can include: KOH – Caustic potash (Potassium hydroxide); K₂CO₃ – Potassium carbonate; KClO₃ – Potassium chlorate; KCl – Muriate of potash (Potassium chloride); KNO₃ – Saltpetre (Potassium nitrate); K₂SO₄– Potassium sulphate; KMnO₄– Potassium permanganate.
Davy’s^(x) accident with nitrogen trichloride didn’t teach him any lessons about safety. His new assistant, Faraday^(xiii), took over preparation and both suffered another accident when it exploded.
Group 1 metals in order of increasing reactivity are lithium, sodium, potassium, rubidium, caesium and francium.
The total weight of seawater on planet earth is about 1.4 Quintillion tonnes (1.4 x 10¹⁸). Potassium makes up about 0.04% of seawater so (1.4 x 0.04/100 x 1018 = 560 x 10¹²) 560 trillion tonnes. Using the short scale: 1 trillion = one followed by 12 zeros = 1,000,000,000,000 written as 10¹²; 1 Quadrillion = 10¹⁵ ; 1 Quintillion = 10¹⁸
Claudia Flavell-While, ‘Fritz Haber and Carl Bosch – Feed the World,’ The Chemical Engineer, March 1, 2010, https://www.thechemicalengineer.com/features/cewctw-fritz-haber-and-carl-bosch-feed-the- world/
‘Introduction to Ammonia Production,’ American Institute of Chemical Engineers, last modified September 2016, https://www.aiche.org/resources/publications/cep/2016/september/introduction-ammonia-production
Jutta Dick, ‘Clara Immerwahr,’ Jewish Women: A Comprehensive Historical Encyclopaedia, Jewish Women’s Archive, retrieved February 20, 2020, https:// jwa.org/encyclopedia/article/ immerwahr-clara
Joule-Thomson effect - When a gas drops from a high pressure to a lower pressure in a closed system, the temperature drops. All real gases (except hydrogen and helium) cool as they expand at normal temperatures and pressures; this phenomenon is often utilised in liquefying gases. By closed system, I mean where no work is done by the expanding gas and no heat is exchanged. By normal temperatures and pressures, I mean those conditions in which the Joule-Thomson cooling effect is observed – a wonderfully circular argument. For more tautological fun see Joule^(xv), Thomson^(xvi) and Grimes^(xiv).
Ounces - One avoirdupois ounce equals 28.35 grams, although precious metals are often measured in troy (or apothecaries’) ounces just to confuse everyone. One troy ounce equals 31.103 grams.
Boyle’s Law - Boyle’s Law tells you that, with all other things constant, the volume of a gas is inversely proportional to the absolute pressure. P₁V₁= P₂V₂. If you quadruple the pressure, the volume reduces to a quarter. Liquids, on the other hand, are almost incompressible. In Leith, the pressure of both liquid and gas was set by the operating conditions of the spheres, so one kilogram of ammonia gas at three atmospheres occupied about 330 times the volume of one kilogram of liquid ammonia. Which meant that a gas pipe had to be almost twenty times the diameter of a liquid pipe to carry the same mass flowrate at the same pressure.
Ammonia liquid in equilibrium with its vapour VLE Chart https://www.engineeringtoolbox.com/ammonia-pressure-temperature-d_361.html
Streptomycin - Streptomycin was the first antibiotic cure for tuberculosis (TB), isolated in 1943 in the USA and trialled in the late 1940s.
Worth his weight in gold - 70kg = 2469 ounces = 2250 troy ounces. Value of gold in 1988 = £250 per troy ounce. Value 70kg gold = 2250 x 250 = £562,500. (Note that in 2020, gold is priced at £1,500 per troy ounce and the same weight would be worth £3,375,000).
DiMeo, Michelle, ‘=“Such a sister became such a brother”: Lady Ranelagh’s influence on Robert Boyle’, in special Boyle issue of Intellectual History Review, 25 (2015), 21–36.