General method

A general method for the synthesis of l -alkenes is provided by the action of a Grignard reagent upon allyl bromide, for example  

The general method to be adopted for the analysis of mixtures of organic compounds is to separate them into their components and to 

Three general methods are available for the preparation of iodides from alcohols — 

In the generalized method of Hayden and O Connell (1975), the pure-component and cross second virial coefficients are given by the sum of two contributions 

The most general method i.s a form of parametric mapping in which the transformation functions, and in Equation (2.26), are polynomials 

One of the general methods for the preparation of acid chlorides is the action of phosphorus pentachloride on the corresponding carboxylic acid  

Originally, general methods of separation were based on small differences in the solubilities of their salts, for examples the nitrates, and a laborious series of fractional crystallisations had to be carried out to obtain the pure salts. In a few cases, individual lanthanides could be separated because they yielded oxidation states other than three. Thus the commonest lanthanide, cerium, exhibits oxidation states of h-3 and -t-4 hence oxidation of a mixture of lanthanide salts in alkaline solution with chlorine yields the soluble chlorates(I) of all the -1-3 lanthanides (which are not oxidised) but gives a precipitate of cerium(IV) hydroxide, Ce(OH)4, since this is too weak a base to form a chlorate(I). In some cases also, preferential reduction to the metal by sodium amalgam could be used to separate out individual lanthanides. 

Sulphur. The general method is to heat the compound at 200-260° with the theoretical amount of sulphur required to bring it to the aromatic state  

E. Vedejs (1978) developed a general method for the sterically controlled electrophilic or-hydroxylation of enolates. This uses a bulky molybdenum(VI) peroxide complex, MoO(02)2(HMPTA)(Py), which is rather stable and can be stored below 0 °C. If this peroxide is added to the enolate in THF solution (base e.g. LDA) at low temperatures, oneO—O bond is broken, and a molybdyl ester is formed. Excess peroxide is quenched with sodium sulfite after the reaction has occurred, and the molybdyl ester is cleaved to give the a-hydroxy car- 

Fischer T H and Almidf J 1992 General methods for geometry and wavefunctlon optimization J. Phys. Chem. 96 9768 

Nitration products. Although no general method of nitration can be given, the following procedure is wddely applicable. 

Needleman S B and C D Wunsch 1970. A General Method Applicable to the Search for Similarities in the Amino Acid Sequences of Two Proteins. Journal of Molecular Biology 48 443-453. 

Note that this is only a particular case of Williamson s general method for the preparation of ethers. 

In 1824 Berzelius, generally credited with the discovery, prepared amorphous silicon by the same general method and purified the product by removing the fluosilicates by repeated washings. Deville in 1854 first prepared crystalline silicon, the second allotropic form of the element. 

A mixture of 0.30 mol of the acetylenic tosylate (prepared according to the general method described in VlII-3, Exp. 3 from the corresponding acetylenic alcohol, which was prepared from HC=CHgBr and CgHi3CH=0 in THF, as described in Ref. l)and 100 ml of dry acetone was added to a solution of 0.40 mol of anhydrous 

Main J, Mandelshtam V A, Wunner G and Taylor H S 1998 Harmonic inversion as a general method for periodic orbit quantization Nonlinearity1015 

Figure 7.2 from Alder B J and TE Wainwright 1959. Studies in Molecular Dynamics. 1. General Method. The Journal of Chemical Physics 31 459-466. 

Most problems in chemistry [all, according to Dirac (1929)] could be solved if we had a general method of obtaining exact solutions of the Schroedinger equation 

In this way the student s knowledge of the organic reactions is consolidated as he proceeds through the sections, his experience of the general method of identification steadily increases, and the investigation of the unknown compounds forms a welcome break from the systematic pursuit of the sectional work. 

Filtration. Before discussing the practical details of the purification of solid substances by recrystallisation, it is convenient to describe here the general methods of filtration. The two principal occasions in organic chemistry when filtration is necessary are  

The BET equation filled an annoying gap in the interpretation of adsorption isotherms, and at the time of its appearance in 1938 it was also hailed as a general method for obtaining surface areas from adsorption data. The equation can be put in the form 

Doebner-von Miller reaction Condensation of an aromatic amine with an aldehyde or ketone in the presence of hydrochloric acid to form a quinoline derivative. A general method, thus aniline and ethanal give 2-methyl-quinoline (quinaldine) and p-phenetidine. 

Boron forms a whole series of hydrides. The simplest of these is diborane, BjH. It may be prepared by the reduction of boron trichloride in ether by lithium aluminium hydride. This is a general method for the preparation of non-metallic hydrides. 

Primary and secondary amines are susceptible to oxidation and replacement reactions involving the N—H bonds. Within the development of peptide synthesis numerous protective groups for N—H bonds have been found (M, Bodanszky, 1976 L.A. Carpino, 1973), and we shall discuss five of the more general methods used involving the reversible formation of 

Since the silver salts of the carboxylic acids are usually soluble in dilute nitric acid, they must be prepared by treating an aqueous solution of a neutral salt of the acid (and not the free acid itself) with silver nitrate solution. It is not practicable to attempt to neutralise the acid with sodium or potassium hydroxide solution, because the least excess of alkali would subsequently cause the white silver salt to be contaminated with brown silver oxide. The general method used therefore to obtain a neutral solution j to dissolve the acid in a small excess of ammonia solution, and then to boil the solution until all free 

---