SUMMARY / RELATED TOPICS

Butadiene

1,3-Butadiene is the organic compound with the formula 2. It is a colorless gas, condensed to a liquid, it is important industrially as a monomer in the production of synthetic rubber. The molecule can be viewed as the union of two vinyl groups, it is the simplest conjugated diene. Although butadiene breaks down in the atmosphere, it is found in ambient air in urban and suburban areas as a consequence of its constant emission from motor vehicles; the name butadiene can refer to the isomer, 1,2-butadiene, a cumulated diene with structure H2C=C=CH−CH3. This allene has no industrial significance. In 1863, the French chemist E. Caventou isolated butadiene from the pyrolysis of amyl alcohol; this hydrocarbon was identified as butadiene in 1886, after Henry Edward Armstrong isolated it from among the pyrolysis products of petroleum. In 1910, the Russian chemist Sergei Lebedev polymerized butadiene and obtained a material with rubber-like properties; this polymer was, found to be too soft to replace natural rubber in many applications, notably automobile tires.

The butadiene industry originated in the years leading up to World War II. Many of the belligerent nations realized that in the event of war, they could be cut off from rubber plantations controlled by the British Empire, sought to reduce their dependence on natural rubber. In 1929, Eduard Tschunker and Walter Bock, working for IG Farben in Germany, made a copolymer of styrene and butadiene that could be used in automobile tires. Worldwide production ensued, with butadiene being produced from grain alcohol in the Soviet Union and the United States, from coal-derived acetylene in Germany. In the United States, western Europe, Japan, butadiene is produced as a byproduct of the steam cracking process used to produce ethylene and other alkenes; when mixed with steam and heated to high temperatures, aliphatic hydrocarbons give up hydrogen to produce a complex mixture of unsaturated hydrocarbons, including butadiene. The quantity of butadiene produced depends on the hydrocarbons used as feed. Light feeds, such as ethane, give ethylene when cracked, but heavier feeds favor the formation of heavier olefins and aromatic hydrocarbons.

Butadiene is isolated from the other four-carbon hydrocarbons produced in steam cracking by extractive distillation using a polar aprotic solvent such as acetonitrile, N-methyl-2-pyrrolidone, furfural, or dimethylformamide, from which it is stripped by distillation. Butadiene can be produced by the catalytic dehydrogenation of normal butane; the first such post-war commercial plant, producing 65,000 tons per year of butadiene, began operations in 1957 in Houston, Texas. Prior to that, in the 1940s the Rubber Reserve Company, a part of the United States government, constructed several plants in Borger, Toledo, El Segundo, California to produce synthetic rubber for the war effort as part of the United States Synthetic Rubber Program. Total capacity was 68 KMTA. Today, butadiene from n-butane is commercially practiced using the Houdry Catadiene process, developed during World War II, it entails treating butane over a chromia at high temperatures. In other parts of the world, including South America, Eastern Europe and India, butadiene is produced from ethanol.

While not competitive with steam cracking for producing large volumes of butadiene, lower capital costs make production from ethanol a viable option for smaller-capacity plants. Two processes were in use. In the single-step process developed by Sergei Lebedev, ethanol is converted to butadiene and water at 400–450 °C over any of a variety of metal oxide catalysts: This process was the basis for the Soviet Union's synthetic rubber industry during and after World War II, it remained in limited use in Russia and other parts of eastern Europe until the end of the 1970s. At the same time this type of manufacture was canceled in Brazil; as of 2017, no butadiene was produced industrially from ethanol. In the other, two-step process, developed by the Russian emigree chemist Ivan Ostromislensky, ethanol is oxidized to acetaldehyde, which reacts with additional ethanol over a tantalum-promoted porous silica catalyst at 325–350 °C to yield butadiene: This process was one of the three used in the United States to produce "government rubber" during World War II, although it is less economical than the butane or butene routes for the large volumes.

Still, three plants with a total capacity of 200 KMTA were constructed in the U. S. with start-ups completed in 1943, the Louisville plant created butadiene from acetylene generated by an associated Calcium Carbide plant. The process remains in use today in India. 1,3-Butadiene can be produced by catalytic dehydrogenation of normal butenes. This method was used by the U. S. Synthetic Rubber Program during World War II; the process was much more economical than the alcohol or n-butane route but competed with aviation gasoline for available butene molecules. The USSRP constructed Lake Charles, Louisiana. Total annual production was 275 KMTA. In the 1960s, a Houston company known as "Petro-Tex" patented a process to produce butadiene from normal butenes by oxidative dehydrogenation using a proprietary catalyst, it is unclear. After World War II, the production from butenes became the major type of production in USSR. 1,3-Butadiene is inconvenient for laboratory use b

John Broadwood

John Broadwood was the Scottish founder of the piano manufacturer Broadwood and Sons. Broadwood was born 6 October 1732 and christened 15 Oct 1732 at St Helens, Cockburnspath in Berwickshire, grew up in Oldhamstocks, East Lothian, he inherited his father James Broadwood's profession, that of a wright or carpenter/joiner, as a young man walked from Oldhamstocks to London, a distance of 400 miles, where he worked for the harpsichord maker Burkat Shudi. Burkat Shudi died in 1773, John Broadwood took control of the company from his brother-in-law in 1783. Broadwood is credited, together with Robert Stodart, founder of another famous firm of piano makers, of helping Americus Backers to perfect the English Grand Action, which remained in use by many makers unchanged for 70 years and, in Broadwoods' case over 100 years, continued in use in various improved forms until the early years of the 20th century. In time his sales of pianos exceeded those of harpsichords, to the point that he ceased to manufacture harpsichords in 1793.

He died in London. Broadwood's other technical innovations in piano manufacture include: adding a separate bridge for the bass notes, patenting the piano pedal in 1783 and expanding the then-standard five octave range upwards by half an octave, in response to a request of Dussek, by half an octave downwards; as a company and Sons prospered, was passed into the hands of his sons, James Shudi Broadwood and Thomas Broadwood. John married Shudi's daughter Barbara in 1769, they had four children Barbara died. He married Mary Kitson in 1781 and had a further six children. Many of his descendants were involved in pianoforte manufacturing in England and some were involved in the British Army in India during the reign of Queen Victoria. Others emigrated to Australia; the Broadwood family tree can be traced back to circa 1580. The British general Robert George Broadwood was a grandson by his son Thomas and Mary Athlea Matthews. Piano: An Encyclopedia, page 57 Pianos and Their Makers by Alfred Dolge, page 244 ISBN 0-486-22856-8 Broadwood by Appointment" by David Wainwright, Quiller Press, London 1982 John Broadwood and Sons, official website John Broadwood and Sons Piano Manufacturers by Sally Jenkinson, Surrey County Council John Broadwood & Sons - The Piano in Polish Collections

Aguilaria

Aguilaria is a genus of sea snails, marine gastropod mollusks in the family Pseudomelatomidae. Species within the genus Aguilaria include: Aguilaria subochracea Taylor J. D. & Wells F. E.. A revision of the crassispirine gastropods from Hong Kong. In: B. Morton The malacofauna of Hong Kong and southern China III. Proceedings of the Third International workshop on the malacofauna of Hong Kong and Southern China. 101-116 Tucker, J. K.. "Catalog of recent and fossil turrids". Zootaxa. 682: 1–1295. Bouchet, P.. A new operational classification of the Conoidea. Journal of Molluscan Studies. 77: 273-308