SU432115A1 - Method of producing urea-aldehyde fertilizers - Google Patents

Description

one

The invention relates to the field of urea-aldehyde fertilizer production from urea and aldehyde components.

A known method for producing urea-aldehyde fertilizers by mixing urea with acetaldehyde, followed by neutralization of the obtained product.

The proposed method differs from the known one in that isobutyl oil is used as the raw material of the aldehyde component. This provides a slow-acting fertilizer with a high digestibility index.

Example. For the experiment, take 500 ml of isobutyl oil of the following composition (in wt.%):

Methanol1,5

Propanol14,2

P-butanol12,4

Isobutanol 45.8

Higher alcohols 15.1

Water11

which is passed through a laboratory setup to obtain aldehydes.

The catalyst is silver. Volume velocity 500/50 10 cm / cm / hour (counting on a liquid mixture of alcohols). The temperature on the top layer of the catalyst is 650 ° C, at the exit 700 ° C. An increase in temperature causes a fire. A mixture consisting of 81% aldehydes is obtained; 0.8% organic acids; 18.2% alcohols (calculated on a dry product). The yield is 78.9%.

The laboratory setup is difficult to regulate flows; In an industrial formaldehyde installation, better results can be achieved.

1 kg of technical urea at a temperature

40 ° C is dissolved in water to a concentration of 60% by weight and acidified with orthophosphoric acid to a pH of 3.5. The solution is heated to a temperature of 50 ° C and the resulting aldehyde mixture is poured in slowly with iptensive stirring. The molar ratio of urea to aldehyde (in terms of isobutyraldehyde) is 1: 8. Next, the reactor is cooled. The temperature at the end of the reaction is 55 ° C. The reaction time is 30 minutes. Then the liquid is filtered off. The solid phase is mixed with powdered dolomite (Ca. Mg / CO2), and the amount of the latter in the dry product is 2.8%; dried at a temperature of 60-70 ° C; granulate to a granule diameter of 3 mm. Output

aldehyde to obtain diurea (in terms of isobutyraldehyde) 96.8%. A slow-acting fertilizer was obtained with the following characteristic: total nitrogen 32 wt.%; water soluble nitrogen

8.32 wt.% Or 26% (total nitrogen); in hot

water soluble nitrogen 30.2%; digestibility index of 93%.

The following optimal parameters are established;

the molar ratio of aldehyde: urea (in terms of pa isomaldehyde aldehyde) 1: (8-10); higher ratios slightly increase the aldehyde product yield, but overload the equipment;

The pH of the solution when using phosphoric acid is 3.4-3.6; with the use of sulfuric acid 3.0-3.2;

the initial reaction temperature is 50 ° C, the final 55 ° C;

urea concentration in an aqueous solution of 60-65%;

reaction time 20-30 minutes; with a longer time, free urea begins to precipitate and the absorption index decreases;

Dolomite is used as a neutralizer with the content of Ca, Mg / CO2 in the final dry product of 2-4%, since the gradual action of the fertilizer requires a woolen environment in field conditions.

A product is obtained consisting of a diurea mixture of aldehydes, which is non-toxic and contains: total nitrogen 31.8-33.2 wt.%; water-soluble nitrogen 24-28% (total nitrogen); in hot water, soluble nitrogen is 30–31 wt.%; digestibility index of 91-97%. The product yield (aldehyde) 96-98%.

Subject invention

A method of producing urea-aldehyde fertilizers by mixing urea with aldehyde components, characterized in that, in order to obtain a slow-acting fertilizer with a high digestibility index, isobutyl oil is used as the raw material of the aldehyde component.