Determination of Copper in Raw Materials Used in the Rubber Industry

1950 ◽  
Vol 23 (4) ◽  
pp. 972-974
Author(s):  
J. Genova ◽  
A. Addobbati
Keyword(s):  
Raw Materials ◽  
Colorimetric Method ◽  
Gum Arabic ◽  
Ammonium Hydroxide ◽  
Sodium Diethyldithiocarbamate ◽  
Repeated Treatment ◽  
Cent Solution ◽  
Materials Used ◽  
Determination Of Copper

Abstract Because of its catalytic action on the deterioration of rubber, the presence of copper in rubber products, even in very small quantities (0.001 per cent), may lead to serious difficulties which shorten the useful life of the products. Most of the raw materials used in the manufacture of these products contain small percentages of copper, and its determination is best made by the colorimetric method. Various reagents can be used for this purpose, among them dithizone (phenylazothionoformic acid phenylhydrazide) and sodium diethyldithiocarbamate. The use of the latter was proposed by Callan and Henderson. The method specified by the A.S.T.M. for the determination of copper in rubber products is based on their work. This method may be briefly described as follows. The destruction of the organic matter and dissolution of the sample is effected by digestion with sulfuric acid in a Kjeldahl flask, followed by treatment with fuming nitric acid and hydrogen peroxide. Repeated treatment and final evaporation to the point where white fumes are evolved eliminates any colored substances and any excess of oxidizing agents. The sesquioxides are precipitated by ammonium hydroxide, and an aliquot part of the filtrate obtained is transferred to a Nessler tube. One cc. of 5 per cent solution of gum arabic, 10 cc. of ammonium hydroxide (d. 0.90), and 10 cc. of 0.1 per cent solution of sodium diethyldithiocarbamate are added. The presence of copper is indicated by the formation of its gray colored carbamate, which, because of its colloidal nature, remains in suspension.

Collaborative Study Using a ZDBT Colorimetric Method for the Determination of Copper in Alcoholic Products

1967 ◽  
Vol 50 (2) ◽  
pp. 334-338
Author(s):  
Duane H Strunk ◽  
A A Andreasen
Keyword(s):  
Sulfuric Acid ◽  
Carbon Tetrachloride ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Good Precision ◽  
Determination Of Copper

Abstract Results are given on a collaborative study in which a zinc dibenzyldithiocarbamate (ZDBT) colorimetric method is used to measure copper in alcoholic products such as high wine, spirits, gin, whisky, brandy, rum, and wine. In this method, the sample is made ca 0.SN with sulfuric acid, and carbon tetrachloride containing 0.2% ZDBT is added. The colored copper-ZDBT complex is extracted in the carbon tetrachloride and measured at 438 mμ against a similar carbon tetrachloride extract of a blank. Data show good precision, and it is recommended that the ZDBT method be adopted as official, first action.

Influence of the Position of Ignition Source on the Raw Materials Used to Produce Biofuel in Form of Wood Pellets

2014 ◽  
Vol 693 ◽  
pp. 335-339
Author(s):  
Jozef Horváth ◽  
Karol Balog ◽  
Tomáš Chrebet
Keyword(s):  
Raw Materials ◽  
Beech Wood ◽  
Ignition Source ◽  
Wood Pellets ◽  
Hot Air ◽  
Spruce Wood ◽  
Loss Of Weight ◽  
Materials Used ◽  
Picea Excelsa

The aim of present work is monitoring thermal decomposition tested samples depending on distance of ignition source, subsequent generation of flame and flameless combustion. Tested samples are used to produce biofuel in form of pellets, which can be made of spruce wood (Picea excelsa, L.) and beech wood (Fagus sylvatica) and have a direct effect on the properties of these pellets. Measurements are carried out according to standard STN ISO 871:2010 Determination of ignition temperature using a hot-air furnace. External ignition source (electrically heated spiral of the wire canthal) is used to analyze different conditions of test samples. Distance between external ignition source and tested samples is 10, 50 and 90 mm. The experiments are performed at an air flow rate 38, 25, 12,5 and 0 mm.s-1. The results show the rate of loss of weight and the flow rates of the material of the test samples at the different test conditions.

A Simplification and Improvement in the Determination of Copper in Fabrics and Rubberized Materials

1932 ◽  
Vol 5 (3) ◽  
pp. 356-359
Author(s):  
F. Kirchhof
Keyword(s):  
Nitric Acid ◽  
Colorimetric Method ◽  
Test Solution ◽  
Ferric Ion ◽  
The Past ◽  
Equivalent Quantity ◽  
Determination Of Copper

Abstract The determination of small quantities of copper in fabrics and in rubberized materials can be simplified by destruction with concentrated nitric acid, which accelerates the ignition to the final ash. At the same time, this method avoids the usual danger of volatilization of copper as chloride as a result of the presence of chlorine from white factice or from cold vulcanization. Likewise, precipitation of the copper as sulfide can be avoided by repeating the precipitation of the extract from the ash, which contains predominantly aluminum and iron, with ammonia. In this second precipitation, only around 1 to 2 per cent of the total quantity of copper is retained in the precipitate and filter, and this quantity may in most cases be neglected. The ordinary colorimetric method used in the past for the detection of copper as complex cuprammonium ion can be made about ten times as sensitive by making use of the reaction: Cu+ + + 2I− → CuI + I. This is, however, applicable only in the complete absence of the ferric ion and of nitric acid in the test solution. The sensitivity can be increased still more by the addition of starch. Another advantage of the determination of copper by measurement of the equivalent quantity of iodine lies in the fact that, if necessary, only one-tenth as much sample need be used, but in this case as in all such determinations, the copper must be distributed uniformly throughout the material to be analyzed.

Gas-Liquid Chromatographic Determination of Volatile Phenols in Matured Distilled Alcoholic Beverages

1983 ◽  
Vol 66 (1) ◽  
pp. 62-70
Author(s):  
Matti Lehtonen
Keyword(s):  
Raw Materials ◽  
Chromatographic Determination ◽  
Alcoholic Beverages ◽  
Gas Liquid Chromatography ◽  
Discriminant Functions ◽  
Volatile Phenols ◽  
Liquid Chromatographic Determination ◽  
Materials Used ◽  
Liquid Chromatographic

Abstract Volatile phenols in matured spirits were determined by gas-liquid chromatography as their 2,4-dinitrophenyl derivatives. Phenol, o-cresol, m-cresol, p-cresol, guaiacol, p-ethylphenol, p-ethylguaiacol, eugenol, and p-(n-propyl)guaiacol, which occurs only in dark rum, were studied at concentrations ranging from 0 to 2 ppm depending on the phenol and the beverage. Scotch, Spanish, and Japanese whiskies, unlike other whiskies examined, contained o-, m-, and p-cresols. Cresols occur in whiskies as a consequence of the raw materials used, in particular peated malt. The level of p-ethylguaiacol is usually somewhat higher in cognac and other brandies than in whiskies. Dark rums differ from the other spirits examined in containing p-(n-propyl)guaiacol, and, typically, higher levels of p-ethylphenol, p-ethylguaiacol, and eugenol. These phenols also occur in higher quantities in some white rums than in whiskies and brandies. Two discriminant functions were obtained by discriminant analysis, which did not, however, allow the spirits to be classified adequately into their respective groups. By using these functions, 82% of the whiskies, 57% of the brandies, and 50% of the rums were correctly grouped.

FTIR spectroscopy for determination of the raw materials used in wood pellet production

Fuel ◽  
2022 ◽  
Vol 313 ◽  
pp. 123017
Author(s):  
Giuseppe Toscano ◽  
Vittorio Maceratesi ◽  
Elena Leoni ◽  
Pierluigi Stipa ◽  
Emiliano Laudadio ◽  
...  
Keyword(s):  
Ftir Spectroscopy ◽  
Raw Materials ◽  
Wood Pellet ◽  
Pellet Production ◽  
Materials Used

AMERICAN EXPERIENCE AND PROBLEMS OF THE TAXATION OF SMALL BUSINESS

2018 ◽  
Author(s):  
Sergey Kaledin ◽  
Ekaterina Shestakova
Keyword(s):  
Small Business ◽  
Inventory Management ◽  
Raw Materials ◽  
The United States ◽  
Optimal Order ◽  
Accounting System ◽  
American Experience ◽  
The Usa ◽  
Materials Used

Development of small business in the USA can be connected with a number of the reasons among which it is possible to call as the features of historical character connected with emergence and development of the United States and the reasons of tax character. So, in each state privileges on taxes which allow to organize in the best way by use of tax planning business can be established. It is represented that the institutionalism is indissoluble with the taxation as in the taxation there are institutes, customs, for example, regarding check of conscientiousness of the taxpayer, use of the special tax treatments and the habits, so at many businessmen and the companies became a habit earlier to pay taxes, to form an overpayment on taxes for the purpose of decrease in risks of additional accrual of penalties, others opposite, created a habit of a conclusion of the capitals abroad to low-tax territories for the purpose of decrease in the tax load. One of the topical problems is the problem of choosing the optimal structure of capital, i.e. determination of the ratio of own and long-term borrowed funds. Production reserves in the Russian accounting system are either goods purchased for later sale, or raw materials used for production. For a financial manager, stocks are immobilized funds, i.e. funds withdrawn from circulation. Without such an immobilization is indispensable, however, indirect losses should be minimized. To minimize the costs of maintaining current stocks at the proper level, the approach based on the concept of the optimal order (delivery) order is used. In the theory of inventory management, special models have been developed to determine the volume of one order lot and the frequency of orders.

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