Copper requirements/recommendations

Copper - Most copper deficiencies are found on organic soils and on sandy soils. Recommended copper application rates range from 1 to 10 kg/ha. Residual effects of copper are very marked, with responses being noted up to 8 years after application, so annual ap-plicationsnsually are not necessary [3]. Soil tests should be used to monitor the copper buildup in soils where copper is applied. Some crops with high copper requirements are cereals, corn, clover, and some fruits and vegetables. 

RECOMMENDED DAILY ALLOWANCE OF COPPER. The estimated copper requirement of man is based on balance studies. On the basis of such studies, and in order to allow for a margin of safety, the National Academy of Sciences- National Research Council, recommends a daily copper intake of 1.5 to 3 mg for adults. The requirement for infants and children has been estimated at between 0.4 and 2.0 mg per day. It is emphasized, however, that intake of copper at this level may be too low for the premature infant, who is always born with low copper reserves. It is suggested that infant bottle formulas contain sufficient copper to furnish 100 micrograms/kg of body weight per day. 

Copper is one of the twenty-seven elements known to be essential to humans (69—72) (see Mineral nutrients). The daily recommended requirement for humans is 2.5—5.0 mg (73). Copper is probably second only to iron as an oxidation catalyst and oxygen carrier in humans (74). It is present in many proteins, such as hemocyanin [9013-32-3] galactose oxidase [9028-79-9] ceruloplasmin [9031 -37-2] dopamine -hydroxylase, monoamine oxidase [9001-66-5] superoxide dismutase [9054-89-17, and phenolase (75,76). Copper aids in photosynthesis and other oxidative processes in plants. 

If conditions are such as to require a duplex tube, it is quite likely that a plain end detail for the tube will not be satisfactory. Grooved or serrated joints are recommended for this type of tube, and the ends should be flared or beaded. Table 10-8 gives recommended flare or bell radii for copper-based alloys. Also see Table 10-8A. In service where galvanic corrosion or other corrosive action may take place on the outside material used in the tube, a ferrule of inside tube... 

Common packaging materials are a potential source of aggressive substance s, and careful selection is recommended to avoid surface deterioration. Where paper is in contact with aluminium, the chloride content should be below 0-05 7o, sulphate content below 0-25 7o, copper content below 0-01% and the pH of aqueous extracts in the range pH 5-5-7-5, in order to avoid corrosion in damp conditions. Papers and felts used in building applications should also conform to this specification as a minimum requirement and be of the highest quality, since metallic copper found in materials of inferior origin can result in severe local galvanic attack of aluminium. 

No specific recommendations can be given about the optimum reaction time. As speeding up reactions is a key motive for employing microwave irradiation, the reaction should be expected to reach completion within a few minutes. On the other hand, a reaction should be run until full conversion of the substrates is achieved. In general, if a microwave reaction under sealed-vessel conditions is not completed within 60 min then it needs further reviewing of the reaction conditions (solvent, catalyst, molar ratios). The reported record for the longest microwave-mediated reaction is 22 h for a copper-catalyzed N-arylation (see Scheme 6.63). The shortest ever published microwave reaction requires a microwave pulse of 6 s to reach completion (ultra-fast carbonylation chemistry see Scheme 6.49). 

Like zinc, copper and its compounds have been used since ancient times, with copper dust, acetate, sulfate and carbonate reported in Egyptian and Hindu prescriptions, and also used by Hippocrates and Galen. Copper arsenite was used in 1892 for anemia and debility. Copper sulfate was recommended to strengthen man, to stimulate the heart and blood vessels, to increase deposition of fat and to treat anemia. The adult requirement is 1.25 mg Cud-1, about one third of which is absorbed. TPN should be supplemented with 0.5—1.5 mg d-1 (adults) and 20 gg (kg weight)-1 d-1 (children). 

Any ferric chloride present is reduced to ferrous by shaking with reduced iron. A thin copper plate serves as cathode, is cleaned with dilute nitric acid, rubbed with cotton-wool and sand, and finally washed with potassium cyanide and then with water. Swedish iron constitutes the anode, and is placed in a porous cell to prevent the spongy carbon, which normally separates from the metal, from reaching the cathode. The sulphur in the metal passes into solution as sulphate, and requires removal at intervals with the anode liquor. A current of 0-08 to 0-2 ampere per sq. decimetre of cathode surface is recommended, the voltage being iron content of-the batfy should not fall below the equivalent of aodut A per cent, of ferrous chloride j... 

---