Ethyl Orange

Other Names Benzenesulfonic acid, p-[[p-(diethylamino)phenyl]azo]-, sodium salt Ethyl orange sodium salt Sodium 4-[[4-(diethylamino)phenyl]azo]benzenesulfonate CA Index Name Benzenesulfonic acid, 4-[[4-(diethylamino)phenyl]azo]-, sodinm salt CAS Registry Number 62758-12-7 Merck Index Number Not listed Chemical Structure 

Chemical/Dye Class Azo Molecular Formula Ci6HigN303SNa Molecular Weight 355.39 pH Range 3.4—4.8 

Solubility Very soluble in water very slightly soluble in ethanol UV-Visible (Xnax) 474 mn Melting Point 3(X)°C Synthesis Synthetic method  

Major Applications Lithographic plate preparation,2 holographic storage, hybrid materials, inks,  

Burkhard, R. K. Urquhart, J. M. Structural specificities in the interactions of some organic ions with serum albumin. J. Am. Chem. Soc. 1952, 74, 202-208. 

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Ethyl Orange (sodium 4,4 -diethylaminophenylazobenzenesulfonate) [62758-12-7] M 355.4, pK st 3.8. Recrystd twice from water. 

Adsorption of azo dyes by the biomass is considered as the first step of their biological reduction [39]. Because of adsorption, the dye is concentrated onto the biomass until its saturation the amount of adsorbed dye is then proportional to the amount of biomass [4CM-2]. Steffan et al. [43] observed that 68% Ethyl Orange was rapidly adsorbed on a microbial consortium immobilized in alginate beads, but only after the addition of glucose or starch the dye was effectively degraded. 

Aldehyde content is considered an important flavor note included in the standard of identities for citrus oils. The flavor strength of an oil is based on the aldehyde content, where higher is better. The two major aldehydes are acetaldehyde and octanal. The quantification of aldehydes is based on the reaction of citral in the sample with a hydroxylamine solution, followed by titration with KOH in the presence of ethyl orange indicator. It is modified from AOAC Method 955.32 (AOAC, 1990c Redd et al., 1986). This method was originally developed for lemon oils however, it is applicable to other citrus oils. 

The method is based on the fact that slightly dissociated acids, such as acetic, tartaric, etc., do not exhibit their acidity towards rr ethyl orange in presence of alcohol. If, then, a definite quantity of alkali is added to a genuine vinegar and the added alkali then neutralised in presence of methyl orange by means of an aqueous-alcoholic solution of sulphuric acid, the amount of the latter will correspond exactly with that of the alkali, since the acetic add liberated from the acetate formed does not react with the indicator. If, however, a vinegar contains free mineral acid, the amount of sulphuric acid required will be diminished in accordance with the quantity of the alkali united with the free mineral acid the amount of the latter will thus correspond with the difference between the alkali added and the sulphuric acid necessary for its neutralisation. 

Gels prepared with Methyl orange Ethyl orange Propyl orange Butyl orange... 

Reed, G. H., and L. B. Rogers Adsorption of Methyl Orange and Ethyl Orange on Tailored Silica Gels. Analytic. Cliem. 37, 861 (1965). 

The acid-base indicator ethyl orange turns from red to yellow over the pH range 3.4 to 4.8. Estimate for ethyl orange. 

Methyl-orange (R = Me) Ethyl-orange (R = Et) Propyl-orange (R = Pr) Butyl-orange (R = Bu)... 

The molecular template idea was based on a paper by Dickey (3a) working with Pauling (3b) in which they described selective silica gel adsorbents. These were prepared by gelling in the presence of indicator molecules such as methyl orange, ethyl orange, etc. While I had never been able to confirm the results given in the paper, the idea stayed with me. 

Erythrosin, disodium salt 4-(p-Ethoxyphenylazo)-w-phenylene-diamine monohydrochloride Ethyl bis(2,4-dimethylphenyl) ethanoate Ethyl Orange Ethyl Red Ethyl Violet... 

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