3,202,478 3. A. 0.1% of sodium carbonate Na2CO3 in aqueous solution aqueous solution. Other compounds of ammonia, such (based on the total quantity of the solution of CuCl2 as (NH4)2CO3, CO(NH2)3. may be used in place of in the reactor 2) is added to the solution in the reactor, ammonium hydroxide NH4OH. The following reaction whereupon the following reaction commences, - will then take place when air is passed into the solution (4CuCl2)--12H2O--6O2--12Cu->4(CuCl2:3Cu(OH)2) as described, (micronised) (2) The air heater 7 is then turned on (if not already running The resulting insoluble tribasic copper chloride is "mi on heat) and delivery of pre-heated air under pressure Cronised' and, after decanting and washing, can be used to the reactor 2 is continued until test samples taken at to carry out the method of manufacture described here intervals of time from the solution within the reactor 10 in above. For all subsequent manufacture in the reactor, show, by comparison with each other, that the reaction no further ammonium hydroxide or other compound of according to Eq. 2 has practically ceased, or has reached ammonia is required. Between 0.05% and 0.1% of its economic limit. When this occurs, sodium carbonate sodium carbonate Na2COs is used instead in the manner in aqueous solution is added to the solution in the reactor already described hereinabove. The ammonium catalyst 2 in order to neutralize the small quantity of residual is employed once only (to start the plant working) and, copper now remaining in solution as CuCl2, since the since micronised tribasic copper chloride for all subse reaction indicated in Eq. 2 will not proceed entirely to quent manufacture is abundantly available, the am completion unless the running time is uneconomically monium catalyst is never used again. The reason for prolonged. The weight of sodium carbonate required this change of catalyst is that the micronised tribasic for this purpose will not usually exceed 5% of the total 20 copper chloride formed when sodium carbonate is used weight of the micronised tribasic copper chloride already as a catalyst possesses an even higher percentage than formed in the reactor 2 by the preceding chemical reac 66% of particles of a size less than three microns, tions. The liquor, containing the micronised tribasic thus giving the product even greater fungicidal activity copper chloride in suspension and approximately 6% than when an ammonium catalyst is used. of sodium chloride in solution, is now discharged from For electro-chemical reasons, the column of bars of the reactor through a delivery pipe 8 and run into suitable metallic copper inside the reactor 2 (all of which, filters for washing, drying and the like in known manner. since they rest upon each other, are in electrical con The air-heater 7 may be of conventional design, includ tact) must, in addition to being immersed in the solution ing an inlet 9 for admitting dust-free atmospheric air of CuCl2 in the reactor, also be exposed to the air above under pressure, a source of supply 10 of heat-energy 30 this solution, i.e., above the level 6, in order that the (e.g., steam, hot water, hot waste gases) and an outlet reaction may proceed efficiently. It has been found for waste 11. The heater 7 may of course be heated that for every 1'0' depth of bars of metallic copper im in any desired manner, such as electrically. mersed in the solution, 1'8' to 2'0' of the bars should The quantity of micronised tribasic copper chloride be exposed to the air inside the reactor above the solu manufactured by the novel method of the invention is tion. The ratio is of the height of the immersed bars approximately four times the quantity of micronised to the height of the exposed bars therefore, approximately tribasic copper chloride added to the reactor at the 1:1.8. New bars of metallic copper are added to the top commencement of operations. Clearly, if X units of of the column as the bars already in the reactor become micronised tribasic copper chloride are added to the 40 used up. - - reactor to commence operations, the yield of micronised - - - Example tribasic copper chloride at the conclusion will be 4X units. Since, however, from this 4X units, X units must 200 lb. of micronised tribasic copper chloride were put always be returned to the reactor in order to repeat the into the reactor. To this, 340 lb. of commercial hy process, the net yield, or quantity manufactured, is 3X drochloric acid containing 30% of HCl were added to units each time the reactor is discharged on completion 45 the reactor, water being added to bring the level of the of the process described above. This is clearly indicated solution up to 30', thus producing a strong aqueous in Eqs. 1 and 2 from which it will be seen that, theoreti solution of micronised CuCl2 in the -reactor. The pre cally, for each equimolar quantity of micronised tribasic heated air delivery to the reactor was started and, after copper chloride added to the reactor (see Eq. i., four one hour's running time and with the pre-heated air equimolar quantities are yielded (see Eq. 2). 50 still being delivered to the reactor, 1 lb. of sodium car In order to start the process in the first instance, and bonate in aqueous solution was added as a catalyst to the thereafter to repeat it, an initial quantity of micronised solution of micronised CuCl2 in the reactor, when the tribasic copper chloride must be made. This can be done reaction indicated in Eq. 2 commenced. The pre-heated by taking a given molar quantity of ordinary tribasic air delivery was continued for a further three hours (mak copper chloride (i.e., as manufactured by the known 55 ing a total of four hours running time) when test samples method of chemical precipitation) and adding thereto the taken from the solution in the reactor showed that the molar quantity of hydrochloric acid required to bring reaction had proceeded as far as was practicable. With the pre-heated air still being delivered to the reactor, 15 it into solution. lb. of sodium carbonate in aqueous solution were then CuCl3Cu(OH)--6HC1->4CuCl2-4-6H2O (3) 60 added to the (now very weak) aqueous solution of CuCl2 If one attempts to oxidise the resulting solution of CuCl2 in the reactor, when the following reactions took place, to tribasic copper chloride by passing therethrough either cold or heated atmospheric air under pressure and bubbling such air from the bottom upwards through the +4NaCl--CO, (5) solution in which are immersed bars of metallic copper, 65 2CuCl2-1-3 (Cu(OH)3. CuCOs)--3HO only an extremely slow reaction takes place and the ->2(CuCl2:3Cu(OH)2)--3CO (6) solution therefore changes only very slowly, while the thus precipitating a very small quantity (approximately product thus obtained is of a relatively coarse nature, 20 lb.) of ordinary (i.e., not micronised). tribasic copper since it is not micronised. If, however, a small quantity chloride. The reactor was then discharged, the mi of a suitable soluble catalyst is added to the Solution, 70 cronised tribasic copper chloride washed, dried and the reaction will take place to form micronised tribasic weighed, and found to be 710 lb. Therefore, the actual, copper chloride when air is passed into the solution in or net, yield was 710-200-510 lb. After drying, and the manner described. A suitable catalyst is ammonium . when analysed, the copper content of this batch of hydroxide NH4OH, containing approximately 0.1% by micronised tribasic copper chloride was found to be weight of NH3 based on the weight of CuCl2 in the 75 58.9% and the chlorine content was found to be 16.53%, 3,202,478 S 6 the hydrochloric acid and sodium carbonate consump It is much easier to prepare and apply than Bordeaux tion being respectively 0.68 lb. and 0.033 lb. per lb. of mixture, since it is a free flowing powder and it is ready micronised tribasic copper chloride manufactured. for immediate use by stirring into water and will not set It will be evident that to carry out this process, the acid tle out during spraying. It is also much less corrosive to proof reactor can be of any size provided the fundamental Spray nozzles, and will not cause blockage. conditions are fulfilled. The acid-proof reactor as de 5 The following are some of the crop diseases which can scribed hereinabove is 8’6” tali and 3’6” in diameter, with be controlled by Microcop. The concentrations of Micro an open top, can manufacture 2,040 lb. of micronised tri cop given, in Ibs. per 100 gals. water, are for use with basic copper chloride containing 58.9% of copper per day high voluime sprayers, at a rate of 100 gals. spray per acre, of twenty working hours (five hours per batch). (A total liness otherwise stated. If low volume equipment is em of one hour is required for charging and discharging the 0. ployed, the concentration should be adjusted to suit the reactor.) This reactor forms part of a small pilot plant sprayer by reducing the amount of water. from which the foregoing data has been obtained. It will also be evident that long acid-proof channels, filled with - Lbs. per Renarks bars of metallic copper and fitted for preheated air de Crop Disease 100 Gals.