Crotonic add

A. sec-Butyl crotonate. In a 2-1. round-bottomed flask are placed 258 g. (3 moles) of crotonic add (Note 1), 370 g. (5 moles) of sec-butyl alcohol in which has been dissolved 6-7 ml. of concentrated sulfuric acid, and 300 ml. of benzene. A few boiling chips are added, and the flask is fitted with a suitable water separator (Note 2) in the top of which is placed a reflux condenser. The mixture is heated under reflux for about 12 hours or until no further separation of aqueous phase occurs. About 65 ml. of water is collected. The cooled reaction mixture is diluted with 200 ml. of ether, washed with 10% sodium carbonate solution... 

Eastman Organic Chemicals practical grade of crotonic add (containing 10% water) was used by the checkers without further purification. 

Crotonic add, esterification with sec-butyl alcohol, 41, 60 Crystal Violet, from condensation of oxalyl chloride with dimethyl-aniline, 41, 2-4... 

The adsorption of sodium polyacrylate on kaolinite was investigated by Michaels and Morelos1105 in the pH range 5-8. Adsorbance was found to decrease with rising pH and to increase in proportion to M0 05. Schmidt and Eiriehm) dealt with a series of vinyl aeetate-crotonic acid copolymers adsorbed on anatase as a function of the charge density of copolymer and the pH of solution. Adsorbance largely increased as the crotonic add content was raised and also as the pH was lowered. 

Cognate preparations. Crotonic add [(E) ]-But-2-enoic acid. Mix together in a 250-ml flask carrying a reflux condenser and a calcium chloride drying tube 25 g (32 ml, 0.57 mol) of freshly distilled acetaldehyde with a solution of 59.5 g (0.57 mol) of dry, powdered malonic acid in 67 g (68.5 ml, 0.85 mol) of dry pyridine to which 0.5 ml of piperidine has been added. Leave in an ice chest or refrigerator for 24 hours. Warm the mixture on a steam bath until the evolution of carbon dioxide ceases. Cool in ice, add 60 ml of 1 1 sulphuric acid (by volume) and leave in the ice bath for 3-4 hours. Collect the crude crotonic acid (c. 27 g) which has separated by suction filtration. Extract the mother-liquor with three 25 ml portions of ether, dry the ethereal extract, and evaporate the ether the residual crude acid weighs 6g. Recrystallise from light petroleum, b.p. 60-80 °C the yield of crude crotonic acid, m.p. 72 °C, is 20 g (41%). 

Reaction of a.Q-unsaturated acids with ketones.3 Lithium naphthalenide in the presence of diethy famine reacts with a,/ -unsaturated adds, for example crotonic add (1), to give the ot-anion of lithium crotonate. This anion reacts with ketones, for example cyclohexanone (2), to give 5-hydroxy acids, for example <5(1 -hydroxycyclohex-l -yl)-crotonic acid (3). 

The two H NMR spectra shown here belong to crotonic add(trons-CH3CH=CHCOOH) and methacrylic acid [H2C=C(CH3)COOH]. Which spectrum corresponds to which acid ... 

ETHYL P-ANILINOCROTONATE (Crotonic add, P-anilino-, ethyl ester)... 

Ethyl Isocrotonate Crotonic add, ethyl ester, (Z)- (8) 2-Butenoic acid, ethyl ester, (Z)- (9) (6776-19-8)... 

The excess nitric acid is used in order to oxidize unchanged crotonic add. Since hydrocyanic acid may be evolved the operation should be carried out under a hood. 

S nva = n-valeric acid iva = isovaleric acid taa = trimethylacetic acid era = crotonic add tga = tiglic acid Saturated straight-chain fatty acids nha = -hexandc acid (caproic add), noa = n-octanoic acid (capryUc add), nda = n-decanoic acid (capric acid), 7-hda = 7-hydroxydecanoic acid, ndoa = n-dodecandc add (lauric acid) nhda = n-hexadecanoic acid (palmitic add), noda = n-octadecanoic add (stearic add), neia = n-eicosanoic acid (arachidic acid)... 

Crotonic Add n (trans-2-butenoic acid, trans- P methacrylic acid) CH3-CH=CHCOOH. A white crystalline solid prepared by the oxidation of crotonaldehyde. It forms copolymers with vinyl acetate, used as hot-melt adhesives. Esters of crotonic acid are used as plasticizers for acrylic and cellulosic plastics. 

Crotonic add was discovered in croton seeds by Pelletier and Caventou by saponifying the oil, adding tartaric acid, and distilling, but was more definitely characterised by T. Schlippe. Crotonitrile C4HSN, present in crude mustard oil, yields on %drolysis with alcoholic potash crotonic add and... 

In addition to chlorophyll a, one also finds chlorophyll c, that is specific to the brown lineage and comprises a mixture of two very closely related forms, chlorophylls Cl and C2- Two essential differences allow us to distinguish between chlorophyll a and chlorophylls c - the tetrapyrrole system of the porphin (dehydrochlorin) and the replacement of the phytyl chains by crotonic add. 

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