Perkin

Prepared by healing benzaldehyde with sodium ethanoate and ethanoic anhydride (Perkin reaction) or with ethyl ethanoate and sodium ethoxide. Occurs in storax, or liquid... 

Perkin reaction A condensation between aromatic aldehydes and the sodium salts of fatty acids or their aromatic derivatives. The reaction between benzaldehyde and sodium ethanoate in the presence of ethanoic anhydride leads to sodium cinnamate... 

X-ray photoelectron spectroscopy (XPS), also called electron spectroscopy for chemical analysis (ESCA), is described in section Bl.25,2.1. The most connnonly employed x-rays are the Mg Ka (1253.6 eV) and the A1 Ka (1486.6 eV) lines, which are produced from a standard x-ray tube. Peaks are seen in XPS spectra that correspond to the bound core-level electrons in the material. The intensity of each peak is proportional to the abundance of the emitting atoms in the near-surface region, while the precise binding energy of each peak depends on the chemical oxidation state and local enviromnent of the emitting atoms. The Perkin-Elmer XPS handbook contains sample spectra of each element and bindmg energies for certain compounds [58]. 

Davis L E, MacDonald N C, Palmberg P W, Riach G E and Weber R E 1976 Handbook of Auger Eiectron Spectroscopy 2nd edn (Eden Prairie, MN Perkin-Elmer Corporation)... 

Marrian C R K, Perkins F K, Brandow S L, Koloski T S, Dobisz E A and Calvert J M 1994 Low voltage electron beam lithography in self-assembled ultrathin films with the scanning tunneling microscope Appi. Rhys. Lett. 64 390... 

Wagner C D, Riggs W M, Davis L E, Moulder J F and Muilenburg G E 1979 Handbook of X-ray Photoelectron Spectroscopy (Eden Prairie, MN Perkin Elmer)... 

Dietel E, Hirsch A, Zhou J and Rieker A 1998 Synthesis and electrochemical investigations of molecular architectures involving Cgg and tetraphenylporphyrin as building blocks J. Chem. See., Perkin Trans. 2 1357-64... 

The 20th century brought important advances in the field of organic chemistry. In the first decades of the century, the syntheses of inaeasingly complex molecules were accomplished. Some notable compounds synthesized during that time were a-terpinol (WH. Perkin, 1904), camphor (G. Komppa, 1903), and tropinone (R. Robinson, 1917 Figure 10.3-28). 

F H, O Kennard, D G Watson, L Brammer, A G Orpen and R Taylor 1987.1 ables of Bond Lengths determined by X-ray and Neutron Diffraction. 1. Bond Lengths in Organic Compounds. Journal of he Chemical Society Perkin Transactions 11 51-519. 

For general work, a very satisfactory apparatus for collecting fractions under reduced pressure is the Perkin triangle C, which is shown in Fig. 14, together with the requisite fittings for the complete... 

G. A. R. Kon Jour. Chem. Soc.., 1930, 182) described a modification of the Perkin triangle having only two taps instead of the three described above. It may be purchased from Quickfit Quartz, Ltd., Quickfit Woiks, Stone, Staffs. 

Cinnamic Acid. CeH5CH CH COOH. (Perkin s Reaction.)... 

Cinnamic acid is usually prepared by Perkin s reaction, benzaldehyde being heated with sodium acetate in the presence of acetic anhydride. It is probable that the benzaldehyde and the acetic anhydride combine under the catalytic action of the sodium acetate, and the product then readily loses water to give mono-benzylidene acetic anhydride (. ). The latter, when subsequently... 

Coumarin is usually prepared by heating salicylaldehyde with acetic anhydride and sodium acetate (i.e., the Perkin cinnamic acid synthesis, p. 23 6), whereby the 0" hydroxy-cinnamic acid (I) undergoes cyclisation to coumarin. Coumarins having substituents in the benzene ring can often be similarly prepared. 

The dotted line in Fig. 11,17, 2 refers to the modification of the apparatus for use in fractional distillation under reduced pressure a Perkin triangle or equivalent receiver device ( vacuum distilling adapter ) is generally employed for collection of the various fractions. 

Attach the flask containing the mixture, with capillary in position, to the column make sure that the Perkin triangle (or vacuum distilling adapter ) and receiver are in place. See that the oil pump is functioning... 

The chief disadvantage of the simple vacuum distillation set up shown in Fig. 11,19, 1 is that, if more than one fraction is to be collected, the whole process must be stopped in order to change the receiver B. It is of value, however, for the distillation of solids of low melting point the distillate can easily be removed from the receiver by melting and pouring out. For routine work, involving the collection of several fractious under reduced pressure, the most convenient receiver is the so-called Perkin triangle the complete apparatus for vacuum distillation is depicted in F g. 11,20, 1. The Claisen fla.sk A is fitted to a. short water... 

A set-up for distillation under reduced pressure is shown in Fig. 11,60,3 it is generally more convenient to use a Kon receiver or a Perkin triangle (Fig. 11, 56, 31). The vessel at the side, connected to the assembly by rubber pressure tubing, may be immersed in a Dry Ice-acetone bath and serves as a trap for volatile materials. 

Liberate the free base by adding to the phenylhydrazine hydrochloride 125 ml. of 25 per cent, sodium hydroxide solution. Extract the phenyl-hydrazine with two 40 ml. portions of benzene, dry the extracts with 25 g. of sodium hydroxide pellets or with anhydrous potassium carbonate thorough drying is essential if foaming in the subsequent distillation is to be avoided. Most of the benzene may now be distilled under atmospheric pressure, and the residual phenylhydrazine under reduced pressure. For this purpose, fit a small dropping funnel to the main neck of a 100 ml. Claisen flask (which contains a few fragments of porous porcelain) and assemble the rest of the apparatus as in Fig. II, 20, 1, but do not connect the Perkin triangle to the pump. Run in about 40 ml. of the benzene, solution into the flask, heat the latter in an air bath (Fig. II, 5, 3) so that... 

Perkin reaction. The condensation of an aromatic aldehyde with an acid anhydride in the presence of the sodium or potassium salt of the acid... 

It is interesting to note that altliough cis-lrans isomerism about the double bond is theoretically possible in cinnamic acid, the Perkin reaction gives rise only to the trans form, m.p. 133°, the cis form, m.p. 68° (termed aHo-cinnamic acid) being unstable and easily converted into the trails acid. 

Basic catalysts other than alkali acetates have been employed in the Perkin reaction thus salicylaldehyde condenses with acetic anhydride in the presence of triethylamine to yield coumarin (tlie lactone of the cis form of o-hydroxy-cinnamio acid) together with some of the acetyl derivative of the trans form (o-acetoxycoumaric acid) ... 

Here the phenylacetic anhydride, possessing more reactive a-hydrogen atoms, condenses with benzaldehyde to give a-phenylcinnamic acid. The preparation of the latter is an example of the Oglialoro modiflcation of the Perkin reaction. 

Phthalic anhydride may be used as the carbonyl compound in the Perkin reaction see the preparation of phthalylacetic acid under Ninhytlrin (Section VIII,14),... 

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