From carbonates

Chlorophyll is present in all green plants, and is essential to the life of the plant, as it acts as a catalyst in the photosynthesis of carbohydrates from carbon dioxide and water. 

Glavincevski, B., O.L. Gulder and L. Gardner (1984), Cetane number estimation of diesel fuels from carbon type structural composition . SAE paper No. S4- 34, International fuels and lubricants meeting, Baltimore, MD. 

The element before carbon in Period 2, boron, has one electron less than carbon, and forms many covalent compounds of type BX3 where X is a monovalent atom or group. In these, the boron uses three sp hybrid orbitals to form three trigonal planar bonds, like carbon in ethene, but the unhybridised 2p orbital is vacant, i.e. it contains no electrons. In the nitrogen atom (one more electron than carbon) one orbital must contain two electrons—the lone pair hence sp hybridisation will give four tetrahedral orbitals, one containing this lone pair. Oxygen similarly hybridised will have two orbitals occupied by lone pairs, and fluorine, three. Hence the hydrides of the elements from carbon to fluorine have the structures... 

Aminoazobenzene is freely soluble in methylated spirit, although insoluble in water. For recrystallisation, therefore, dissolve the crude substance in boiling methylated spirit, remove from the water-bath, and then add water drop by drop until the solution becomes just cloudy owing to the separation of the solute replace the solution momentarily on the water-bath until the cloudiness disappears, and then at once remove the solution, and allow it to cool slowly. (Alternatively, the crude dry material can be reciystallised from carbon tetrachloride in the usual way.) Aminoazobenzene is thus obtained as yellowish-brown crystals, m.p. 126° yield, 5 g. 

Chill the concentrated solution of the amine hydrochloride in ice-water, and then cautiously with stirring add an excess of 20% aqueous sodium hydroxide solution to liberate the amine. Pour the mixture into a separating-funnel, and rinse out the flask or basin with ether into the funnel. Extract the mixture twice with ether (2 X25 ml.). Dry the united ether extracts over flake or powdered sodium hydroxide, preferably overnight. Distil the dry filtered extract from an apparatus similar to that used for the oxime when the ether has been removed, distil the amine slowly under water-pump pressure, using a capillary tube having a soda-lime guard - tube to ensure that only dry air free from carbon dioxide passes through the liquid. Collect the amine, b.p. 59-61°/12 mm. at atmospheric pressure it has b.p. 163-164°. Yield, 18 g. 

A brisk effervescence of COg without the formation of a precipitate indicates urea (if the NaOH used is free from carbonate). 

Method 2. Place 0-2 g. of cupric acetate, 10 g. of ammonium nitrate, 21 2 g. of benzoin and 70 ml. of an 80 per cent, by volume acetic acid -water solution in a 250 ml. flask fitted with a reflux condenser. Heat the mixture with occasional shaking (1). When solution occurs, a vigorous evolution of nitrogen is observed. Reflux for 90 minutes, cool the solution, seed the solution with a crystal of benzil (2), and allow to stand for 1 hour. Filter at the pump and keep the mother liquor (3) wash well with water and dry (preferably in an oven at 60°). The resulting benzil has m.p. 94-95° and the m.p. is unaffected by recrystallisation from alcohol or from carbon tetrachloride (2 ml. per gram). Dilution of the mother liquor with the aqueous washings gives a further 1 Og. of benzil (4). 

To prepare triphenylcarbinol from triphenylchloromethane, boil the latter with excess of water for 10 minutes. Filter off the resulting triphenylcarbinol, dry between filter papers, and recrystallise from carbon tetrachloride or alcohol m.p. 162°. The yield is almost quantitative. 

Azlactone of a-acetylaminocinnamic acid. Warm a mixture of 29 g. of acetylglycine, 39-5 g. (37 -5 ml.) of redistilled benzaldehyde (Section IV,115), 15 g. of anhydrous sodium acetate and 67 g. (62 ml.) of acetic anhydride (95 per cent.) in a 500 ml. conical flask (equipped with a reflux condenser) on a water bath with occasional stirring until solution is complete (10-20 minutes). Boil the resulting solution for 1 hour, cool and leave in a refrigerator overnight. Stir the sohd mass of yellow crystals with 60 ml. of cold water, transfer to a Buchner funnel and wash well with cold water. (If the odour of benzaldehyde is stih apparent, wash with a little ether.) Recrystallise from carbon tetrachloride or from ethyl acetate-hght petroleum. The yield of azlactone, m.p. 150°, is 35 g. 

Triiodobenzoyl chloride. Reflux 5 g. of 3 4 5-triiodo-benzoic acid, m.p. 289-290°, gently with 10 ml. of redistilled thionyl chloride for 2 hours. Distil off the excess of thionyl chloride on a water bath, and recrystallise the residue from carbon tetrachloride - light petroleum with the use of a little decolourising charcoal. The yield of the acid chloride (bright yellow needles, m.p. 138°) is 3-8 g. it keeps well in a stoppered bottle. 

Place a mixture of 30 g. of 3 5-dinitrobenzoic acid (Section IV,168 and 33 g. of phosphorus pentachloride in a Claisen flask fit a reflux condenser into the short neck and cork the other neck and side arm (compare Fig. Ill, 31, 1). Heat the mixture in an oil bath at 120-130° for 75 minutes. Allow to cool. Remove the phosphorus oxychloride by distillation under reduced pressure (25°/20 mm.) raise the temperature of the bath to 110°. The residual 3 5-dinitrobenzoyl chloride solidifies on cooling to a brown mass the yield is quantitative. Recrystallise from carbon tetrachloride the yield is 25 g., m.p. 67-68° and this is satisfactory for most purposes. Further recrystallisation from a large volume of light petroleum b.p. 40-60°, gives a perfectly pure product, m.p. 69 -6°. 

There is also the promise of finding large amounts of deep methane formed not from biomass but by some abiological processes from carbonates or even carbides formed from carbon-containing asteroids that hit the earth over the ages under the harsh prebiological conditions of our planet. 

Ethylene (as well as propylene) produced from carbon dioxide subsequently allows ready preparation of the whole array of hydrocarbons, as well as their derivatives and products that have become essential to our everyday life. Whereas the nineteenth century relied mostly on coal for energy as well as derived chemical products, the twentieth century greatly supplemented this with petroleum and nat-... 

This reaction showed certain characteristics which distinguish it from nitrations in solutions of nitric acid in organic solvents. Thus, in changing the solvent from carbon tetrachloride to nitromethane, the rate increased by a factor of only 6, whereas nitration involving the nitronium ion was accelerated by a factor of about 30 when the solvent was changed from acetic acid to nitromethane. It was held that the... 

Organoboranes react with propargylic carbonates. Usually, addition of a base is essential for the Pd-catalyzed reactions of organoboranes, but the reaction with propargylic carbonates proceeds without addition of the base, because methoxide is generated in situ from carbonates. For example, the 1,2,4-triene 80 is prepared by the reaction of alkenylborane under neutral conditions[36]. 

The electrons in a carbon-fluorine bond are drawn away from carbon toward fluorine... 

This behavior stems from the greater stability of secondary compared with primary free radicals The transition state for the step m which a chlorine atom abstracts a hydro gen from carbon has free radical character at carbon... 

Primary alcohols do not react with hydrogen halides by way of carbo cation intermediates The nucleophilic species (Br for example) attacks the alkyloxonium ion and pushes off a water molecule from carbon m a bimolecular step This step is rate determining and the mechanism is Sn2... 

Next an alkyl halide (the alkylating agent) is added to the solution of sodium acetylide Acetylide ion acts as a nucleophile displacing halide from carbon and forming a new carbon-carbon bond Substitution occurs by an 8 2 mechanism... 

To understand the effect of a carbonyl group attached directly to the ring consider Its polarization The electrons m the carbon-oxygen double bond are drawn toward oxy gen and away from carbon leaving the carbon attached to the nng with a partial posi tive charge Using benzaldehyde as an example... 

Step 2 The oxidation step can be viewed as a p elimination Water acts as a base to remove a proton from carbon while the O—Cr bond breaks... 

The mechanism of enolization involves two separate proton transfer steps rather than a one step process m which a proton jumps from carbon to oxygen It is relatively slow m neutral media The rate of enolization is catalyzed by acids as shown by the mechanism m Figure 18 1 In aqueous acid a hydronium ion transfers a proton to the carbonyl oxygen m step 1 and a water molecule acts as a Brpnsted base to remove a proton from the a car bon atom m step 2 The second step is slower than the first The first step involves proton transfer between oxygens and the second is a proton transfer from carbon to oxygen... 

Because carbon is sp hybridized m chlorobenzene it is more electronegative than the sp hybridized carbon of chlorocyclohexane Consequently the withdrawal of electron density away from carbon by chlorine is less pronounced m aryl halides than m alkyl halides and the molecular dipole moment is smaller... 

Of all the monosaccharides d (+) glucose is the best known most important and most abundant Its formation from carbon dioxide water and sunlight is the central theme of photosynthesis Carbohydrate formation by photosynthesis is estimated to be on the order of 10 tons per year a source of stored energy utilized directly or indi rectly by all higher forms of life on the planet Glucose was isolated from raisins m 1747 and by hydrolysis of starch m 1811 Its structure was determined in work culmi nating m 1900 by Emil Fischer... 

To prepare the standard pH buffer solutions recommended by the National Bureau of Standards (U.S.), the indicated weights of the pure materials in Table 8.15 should be dissolved in water of specific conductivity not greater than 5 micromhos. The tartrate, phthalate, and phosphates can be dried for 2 h at 100°C before use. Potassium tetroxalate and calcium hydroxide need not be dried. Fresh-looking crystals of borax should be used. Before use, excess solid potassium hydrogen tartrate and calcium hydroxide must be removed. Buffer solutions pH 6 or above should be stored in plastic containers and should be protected from carbon doxide with soda-lime traps. The solutions should be replaced within 2 to 3 weeks, or sooner if formation of mold is noticed. A crystal of thymol may be added as a preservative. 

One method for measuring the temperature of the sea is to measure this ratio. Of course, if you were to do it now, you would take a thermometer and not a mass spectrometer. But how do you determine the temperature of the sea as it was 10,000 years ago The answer lies with tiny sea creatures called diatoms. These have shells made from calcium carbonate, itself derived from carbon dioxide in sea water. As the diatoms die, they fall to the sea floor and build a sediment of calcium carbonate. If a sample is taken from a layer of sediment 10,000 years old, the carbon dioxide can be released by addition of acid. If this carbon dioxide is put into a suitable mass spectrometer, the ratio of carbon isotopes can be measured accurately. From this value and the graph of solubilities of isotopic forms of carbon dioxide with temperature (Figure 46.5), a temperature can be extrapolated. This is the temperature of the sea during the time the diatoms were alive. To conduct such experiments in a significant manner, it is essential that the isotope abundance ratios be measured very accurately. 

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