U.S. patent application number 14/665871 was filed with the patent office on 2015-07-16 for liquid compositions containing urease inhibitors and aryl alkyl alcohols and methods of making and use thereof.
The applicant listed for this patent is Koch Agronomic Services, LLC. Invention is credited to Richard P. Beatty, Drew R. Bobeck, Kurt D. Gabrielson, Stacey L. Wertz.
Application Number | 20150197460 14/665871 |
Document ID | / |
Family ID | 50099111 |
Filed Date | 2015-07-16 |
United States Patent
Application |
20150197460 |
Kind Code |
A1 |
Gabrielson; Kurt D. ; et
al. |
July 16, 2015 |
LIQUID COMPOSITIONS CONTAINING UREASE INHIBITORS AND ARYL ALKYL
ALCOHOLS AND METHODS OF MAKING AND USE THEREOF
Abstract
The present invention provides improved solvent systems for the
preparation of liquid formulations of urease inhibitors,
specifically NEWT, comprising aryl alkyl alcohols. The solvent
systems provided good solubility of the urease inhibitor as well as
at least one of improved stability, lower flammability, lower
toxicity, improved cold temperature storage, improved handling,
improved adsorption onto and/or solubility with solid media such as
urea. Methods of making and using the compositions are also
provided.
Inventors: |
Gabrielson; Kurt D.;
(Lilburn, GA) ; Wertz; Stacey L.; (Conyers,
GA) ; Beatty; Richard P.; (Newark, DE) ;
Bobeck; Drew R.; (Doraville, GA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Koch Agronomic Services, LLC |
Wichita |
KS |
US |
|
|
Family ID: |
50099111 |
Appl. No.: |
14/665871 |
Filed: |
March 23, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13968318 |
Aug 15, 2013 |
|
|
|
14665871 |
|
|
|
|
Current U.S.
Class: |
71/28 |
Current CPC
Class: |
C05G 3/00 20130101; Y02P
60/218 20151101; Y02P 60/21 20151101; C09K 15/06 20130101; C09K
15/26 20130101; C05C 9/00 20130101; C05C 9/02 20130101; C05G 3/90
20200201; C05C 9/02 20130101; C05G 3/90 20200201; C05C 9/00
20130101; C05G 3/90 20200201; C05C 9/02 20130101; C05G 3/90
20200201; C05C 9/00 20130101; C05G 3/90 20200201 |
International
Class: |
C05G 3/08 20060101
C05G003/08; C05C 9/00 20060101 C05C009/00 |
Claims
1. A solid urea-based fertilizer composition comprising: a. urea;
b. from about 0.02 wt. % to about 0.12 wt. % NBPT based on the
total weight of the fertilizer composition; and c. from about 0.03
wt. % to about 0.35 wt. % aryl alkyl alcohol based on the total
weight of the fertilizer composition, wherein said aryl alkyl
alcohol has the general formula (II) ##STR00002## and further
wherein each of R.sub.1-R.sub.5 can be hydrogen, deuterium,
fluorine, bromine, iodine, chlorine, or an alkyl group.
2. A solid urea-based fertilizer composition comprising: a. urea;
b. from about 0.02 wt. % to about 0.12 wt. % NBPT based on the
total weight of the fertilizer composition; c. from about 0.03 wt.
% to about 0.35 wt. % aryl alkyl alcohol based on the total weight
of the fertilizer composition, wherein said aryl alkyl alcohol has
the general formula (II) ##STR00003## and further wherein each of
R.sub.1-R.sub.5 can be hydrogen, deuterium, fluorine, bromine,
iodine, chlorine, or an alkyl group; and d. about 0.005 wt. % to
about 0.25 wt. % glycol based on the total weight of the fertilizer
composition.
3. The urea-based fertilizer composition of claim 1 or claim 2,
wherein the aryl alkyl alcohol is benzyl alcohol.
4. The urea-based fertilizer composition of claim 2, wherein the
glycol is propylene glycol.
5. The urea-based fertilizer composition of claim 1 or claim 2,
further comprising a dye.
6. The urea-based fertilizer composition of claim 1, wherein the
NBPT is present from about 0.05 wt. % to about 0.1 wt. % based on
the total weight of the fertilizer composition, and the aryl alkyl
alcohol is present from about 0.07 wt. % to about 0.3 wt. % based
on the total weight percent of the fertilizer composition.
7. The urea-based fertilizer composition of claim 2, wherein the
NBPT is present from about 0.05 wt. % to about 0.1 wt. % based on
the total weight of the fertilizer composition; the aryl alkyl
alcohol is present from about 0.07 wt. % to about 0.3 wt. % based
on the total weight percent of the fertilizer composition; and the
glycol is present from about 0.01 wt. % to about 0.2 wt. % based on
the total weight percent of the fertilizer composition.
8. The urea-based fertilizer composition of claim 6 or claim 7,
further comprising a dye.
9. A solid urea-based fertilizer granule composition comprising: a.
a urea fertilizer granule; and b. an additive composition
substantially coated on the surface of said fertilizer granule,
wherein said additive composition comprises: i. from about 0.02 wt.
% to about 0.12 wt. % NBPT based on the total weight of the
fertilizer composition; and ii. from about 0.03 wt. % to about 0.35
wt. % aryl alkyl alcohol based on the total weight of the
fertilizer composition, wherein said aryl alkyl alcohol has the
general formula (II) ##STR00004## and further wherein each of
R.sub.1-R.sub.5 can be hydrogen, deuterium, fluorine, bromine,
iodine, chlorine, or an alkyl group.
10. The solid urea-based fertilizer granule composition of claim 9
wherein the additive composition further comprises from about 0.005
wt. % to about 0.25 wt. % glycol based on the total weight of the
fertilizer composition.
11. The Solid urea-based fertilizer granule composition of claim 9
or claim 10, wherein the aryl alcohol is benzyl alcohol.
12. The solid urea-based fertilizer granule composition of claim
10, wherein the glycol is propylene glycol.
13. The solid urea-based fertilizer granule composition of claim 9
wherein the additive composition comprises NBPT present from about
0.05 wt. % to about 0.1 wt. % based on the total weight of the
fertilizer composition, and aryl alkyl alcohol present from about
0.07 wt. % to about 0.3 wt. % based on the total weight percent of
the fertilizer composition.
14. The solid urea-based fertilizer granule composition of claim
10, wherein the additive composition comprises NBPT present from
about 0,05 wt. % to about 0.1 wt. % based on the total weight of
the fertilizer composition; aryl alkyl alcohol present from about
0.07 wt. % to about 0.3 wt. % based on the total weight percent of
the fertilizer composition; and glycol present from about 0.01 wt.
% to about 0.2 wt. % based on the total weight percent of the
fertilizer composition.
15. The solid urea-based fertilizer granule composition of claim 9
or claim 10, wherein a portion of the additive composition
penetrates into the surface of said fertilizer granule.
16. The solid urea-based fertilizer granule composition of claim 9
or claim 10, wherein the additive composition further comprises a
dye.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C.
.sctn.119(e) from U.S. Provisional Application 61/683,367, filed
Aug. 15, 2012, which is incorporated by reference in its entirety
herewith.
BACKGROUND OF THE INVENTION
[0002] Granular fertilizers have been used for some time to provide
nitrogen to the soil. The most widely used and agriculturally
important nitrogen fertilizer is urea. Most of the urea currently
produced is used as a fertilizer in its granular (or prilled) form.
However, after its application to soil, its hydrolysis to yield
ammonia and carbon dioxide occurs. This process is catalyzed by the
enzyme urease, which is produced by some bacteria and fungi. The
gaseous products formed by the hydrolysis reaction (ammonia and
carbon dioxide) volatilize to the atmosphere and thus, substantial
losses from the total amount of the nitrogen applied to the field
occur. The hydrolysis process can be considerably decelerated by
urease inhibitors that are applied together with urea. Urease
inhibitors can also be used in combination with nitrification
inhibitors. Nitrification inhibitors are compounds which inhibit
the conversion of ammonium to nitrate and reduce nitrogen losses in
the soil. Examples of nitrification inhibitors include,
dicyandiamide (DCD).
[0003] Examples of urease inhibitors are the thiophosphoric
triamide compounds disclosed in the U.S. Pat. No. 4,530,714,
including N-(n-butyl)thiophosphoric triamide (NBPT), the most
developed representative of this class of compounds. When
incorporated into a urea-containing fertilizer, NBPT reduces the
rate at which urea is hydrolyzed in the soil to ammonia. The
benefits realized as a result of the delayed urea hydrolysis
include the following: (1) nutrient nitrogen is available to the
plant over a longer period of time; (2) excessive build-up of
ammonia in the soil following the application of the
urea-containing fertilizer is avoided; (3) the potential for
nitrogen loss through ammonia volatilization is reduced; (4) the
potential for damage by high levels of ammonia to seedlings and
young plants is reduced; (5) plant uptake of nitrogen is increased;
and (6) an increase in crop yields is attained. The use of NBPT is
commercially available for the use in agriculture and marketed in
such products as the AGROTAIN.RTM. nitrogen stabilizer product
line.
[0004] Industrial grade N-(n-butyl) thiophosphoric triamide (NBPT)
is a solid, waxy compound, and decomposes by the action of water,
acid and/or elevated temperature. Accordingly, its combination with
other solid materials is very difficult. The use of a liquid
formulation of the NBPT is highly desirable because it greatly
facilitates the introduction of the NBPT onto other solid
materials, such as the PERGOPAK.RTM. M used in AGROTMN DRY.RTM. and
formulation with granular urea. The impregnation of NBPT onto a
UFP, such as PERGOPAK.RTM. M or other solids, such as granular urea
requires the NEWT to be introduced into some liquid carrier prior
to being mixed with the solid. The dissolution of NBPT with or
without UFP into liquid urea-containing fertilizers, such as,
urea-ammonium nitrate solutions (ULAN), is also facilitated by
having the NBPT in an easily assimilated liquid formulation.
[0005] However NBPT is very difficult to solubilize in a
concentrated solution. Accordingly, a variety of solvent mixtures
have been tried, including those disclosed in U.S. Pat. Nos.
5,352,265 and 5,364,438 (using N-methyl pyrrolidone, NMP); U.S.
Pat. No. 5,698,003 (using propylene glycol or dipropylene glycol
alone or in combination with NMP or poly(oxy-1,2-ethanediyl)-alpha
(nonylphenyl)omega-hydroxy); and U.S. Pat. No. 8,048,189 (using
ethanolamine, diethanolamine, triethanolamine,
monoisopropanolamine, or diisopropanolamine buffered with acetic
acid); PCT Patent Publication WO 2008000196 (using
dipropyleneglyrol monomethylether, diethyleneglycol
monomethylether, triethyleneglycol monomethylether or
diethyleneglycol monobutylether in combination with
polyvinylpyrrolidone (PVP) or NMP); CA Patent publication 2701995
(using water); U.S. Patent Publication Nos. 20100168256 (using
water); 20100206031 and 20110259068 (using glycerol, aqueous
sorbitol, ethanolamine, diethanolamine or triethanolamine);
20110113842 (using garlic essential oil in combination with sodium
hydroxide or triethanolamine); and 20110233474 (using (S)-ethyl
lactate or propylene carbonate in combination with
tetrahydrofurfuryl alcohol, PVP, NMP, glycerol formal, propylene
glycol and/or water).
[0006] However, both urea and solvents containing hydroxyl groups
are hydroscopic which causes problems with NBPT formulations,
especially with urea. Water can facilitate the decomposition of
N-(n-butyl)thiophosphoric triamide (NBPT) into non-effective
substances. In addition, water causes stickiness, clumping and
caking of urea-based, granular fertilizers which reduces the
flowability of urea-based granular fertilizers, and the like and
complicates their handling. These problems are exacerbated during
storage of these materials.
[0007] Accordingly, at least 10 wt. % of NMP or 0.1% of PVP is
often used either as a co-solvent or as a crystallization
inhibitor. However, amides like NMP and PVP can be health
deleterious. N-methylpyrrolidone is often classified among
teratogenic compounds and accordingly manufacturers must consider
alternative solvents, especially where worker exposure is difficult
to control (see e.g. Chemical & Engineering News: 32 (Jul. 21,
2008)). In addition, PVP has been documented to cause allergic
reactions, particularly when applied to the skin or where it has
come into contact with mucous membranes (see e.g. K. Yoshida et al.
(2008) International Archives of Allergy and Immunology 146 (2):
169-73 (2008); A. Adachi et al. Contact Dermatitis 48 (3): 133-6
(2003); A. C. Ronnau et al. The British Journal of Dermatology 143
(5): 1055-8 (2000)).
[0008] The above mentioned disadvantages are overcome by the
compositions of the present invention which provide compositions
with reduced health risk and/or toxicity, lower volatility and
flammability, increased stability of NBPT and other components in
the composition, the ability to be used stored at lower application
temperatures, and/or using commercially available, low cost
materials as compared to previous the previous art.
[0009] The present invention relates to a composition comprising a
urease inhibitor and an aryl alkyl alcohol solvent. The present
invention also relates to methods of making the compositions and
their use in agricultural applications.
DETAILED DESCRIPTION OF THE INVENTION
[0010] As used herein, the below terms have the following meanings
unless specified otherwise:
1. Abbreviations and Definitions
[0011] It is noted here that as used in this specification and the
appended claims, the singular forms "a," "an," and "the" include
plural reference unless the context clearly dictates otherwise.
[0012] All percentages, parts and ratios are based upon the total
weight of the compositions of the present invention, unless
otherwise specified. All such weights as they pertain to listed
ingredients are based on the active level and, therefore do not
include solvents or by-products that may be included in
commercially available materials, unless otherwise specified. The
term "weight percent" may be denoted as "wt. %" herein. An
molecular weights as used herein are weight average molecular
weights expressed as grams mole, unless otherwise specified.
[0013] As noted above, the present invention provides an improved
formulation for urease inhibitors, for example
N-(alkyl)thiophosphoric triamide urease inhibitors as described in
U.S. Pat. No. 4,530,714, that are useful in agricultural
applications. The present invention also includes thiophosphoric
triainides and phosphoric triamides of the general formula (I)
X=P(NH.sub.2).sub.2NR.sup.1R.sup.2 (1)
where X=oxygen or sulfur, and R.sup.1 and R.sup.2 are independently
selected from hydrogen, C.sub.1-C.sub.12 alkyl, C.sub.3-C.sub.1,
cycloalkyl, C.sub.6-C.sub.14 aryl, C.sub.2-C.sub.12 alkenyl,
C.sub.2-C.sub.12 alkynyl, C.sub.5-C.sub.14 heteroaryl,
C.sub.1-C.sub.14 heteroalkyl, C.sub.2-C.sub.14 heteroalkenyl,
C.sub.2-C.sub.14 heteroalkyl, or C.sub.3-C.sub.12 cycloheteroalkyl
groups.
[0014] It should be understood that the term
N-(alkyl)thiophosphoric triamide as used throughout this
application refers not only to the N-(alkyl)thiophosphoric triamide
in its pure form, but also to commercial grades of the material
which can contain up to 50 percent (or less), preferably not more
than 20 percent, of impurities, depending on the method of
synthesis and purification scheme(s), if any, employed in the
production.
[0015] In one embodiment, the formulation comprises at least one
aryl alkyl alcohol of the general formula (II),
##STR00001##
where R.sub.1, R.sub.2, R.sub.3, R.sub.4, and R.sub.5 can be
hydrogen, deuterium, fluorine, bromine, iodine, chlorine, or alkyl
groups. Examples of aryl alkyl alcohols include, but are not
limited to benzyl alcohol.
[0016] In one aspect, the composition of the present invention
contains 1 wt. % to about 80 wt. % of the phosphoric or
thiophosphoric triamide. In another aspect, the composition of the
present invention contains 10 to 75 wt. % of the phosphoric or
thiophosphoric triamide. In another aspect, the composition of the
present invention contains 20 to 50 wt. % of the phosphoric or
thiophosphoric triamide. In another aspect, the composition of the
present invention contains 30 to 40% w/w of the phosphoric or
thiophosphoric triamide. In one aspect, the phosphoric or
thiophosphoric triamide is N-(n-butyl)thiophosphoric triamide.
[0017] Optionally, the formulation can also contain additional
components, including co-solvents. In one embodiment, the
additional co-solvent is a glycol or glycol derivative. Examples of
glycols can be represented by the general formula
C.sub.nH.sub.2n(OH).sub.2, where n is 2 to 12. In some embodiments,
n is 3. Glycols also include aliphatic dihydroxy(dihydric)alcohols.
Examples of glycols(diols) are ethylene glycol(glycol), propylene
glycol(1,2-propanediol), 1,4-butanediol, 1,5-pentanediol,
1,6-hexanediol, 1,10-decanediol, 1,7-heptanediol, 1,9-nonanediol,
1,8-octanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol,
2,3-butanediol, 2,4-pentanediol, 2,5-hexanediol, 4,5-octanediol and
3,4-hexanediol. Examples of other noncyclic glycols(diols) are
neopenty glycol, pinacol, 2,2-diethyl-1,-propanediol,
2-ethyl-1,3-hexanediol, 2-ethyl-2-butyl-1,3-propanediol,
Isobutylene glycol, 2,3-dimethyl-1,3-propanediol,
1,3-diphenyl-1,3-propanediol, 3-methyl-1,3-butanediol. Examples of
cyclic glycols are 1,4-cyclohexanedimethanol and p-xylylene glycol.
Examples of polyglycols are polyethylene glycols and polypropylene
glycols.
[0018] Examples of glycol(diol) derivatives which are esters are
ethylene glycol monostearate, ethylene glycol distearate, ethylene
glycol amido stearate, propylene glycol monostearate, propylene
glycol dicaprylate, propylene glycol dicaprate diacetate glycol,
dilaurate glycol, dipalmite glycol, diformate glycol, dibutyrate
glycol, dibenzorate glycol, dipalmate glycol, dipropionate glycol,
monoacetate glycol, monopalmitate glycol and monoformate glycol,
Diethylene glycol monostearate is also an ester derivative.
[0019] Examples of polyglycol (polydiol) derivatives which are
esters are polyethylene glycol (PEG) 200-6000 mono and dilaurates,
such as, PEG 600 dilaurate, PEG 600 monolaurate, PEG 1000
dilaurate, PEG 1000 monolaurate, PEG 1540 dilaurate and PEG 1540
monolaurate, polyethylene glycol 200-6000 mono and dioleates, such
as, PEG 400 monoleate, PEG 600 dioleate, PEG 600 monooleate, PEG
1000 monoleate, PEG 1540 dioleate, PEG 1540 monooleate and
polyethylene glycol 200-6000 mono and distearates, such as, PEG 400
distearate, PEG 400 monostearate, PEG 600 distearate, PEG 600
monostearate, PEG 1000 distearate, PEG 1000 monostearate, PEG 1540
distearate, PEG 1540 monostearate and PEG 3000 monostearate.
[0020] Glycerol (glycerine) is a triol glycerol. Examples of
glycerol esters are glycerol monostearate, glycerol distearate,
glycerol monooleate, glycerol monolaurate, glycerol dilaurate,
glycerol dipalmitate, glycerol monopalmitate, glycerol triacetate,
glycerol tribenzoate, glycerol tributyrate, glycerol trimyristate,
glycerol trioleate, glycerol trilaurate, glycerol tripalmitate and
glycerol tristearate.
[0021] The content of the additional solvent in compositions which
contain the same is the remainder of mixture with the composition
of NBPT and at least one aryl alkyl alcohol. Thus in one group of
embodiments, the content of the additional solvent can be between
about 99 percent by weight and about 5 percent by weight, or
between about 70 percent by weight and about 10 percent by weight
together with the combination of the N-(alkyl) thiophosphoric
triamide in the same concentration ranges described for composition
with the aryl alkyl alcohol as the sole solvent. In other
embodiments, the mixed content of the composition of the invention
is between about 99 percent by weight and about 50 percent by
weight, and preferably between about 70 percent by weight and about
80 percent by weight, based upon the only other component of the
formulation being the N-(alkyl) thiophosphoric triamide urease
inhibitor.
[0022] The solvents according to the present invention have
properties that are advantageous for their use in agriculture such
as: (1) improved stability of the active ingredient urease
inhibitor, such as N-(n-butyl) thiophosphoric triamide (NBPT); (2)
excellent solubility characteristics; (3) extremely low
flammability of the solvents; (4) reduced toxicity and/or health
risk relative to the use of NMP and/or PVP which greatly simplifies
the handling and/or storage of the solution; (5) resistance to
solidifying under cold temperatures without the use of additional
crystallization inhibitors; and (6) good adsorption characteristics
onto other solid components such as urea for solid fertilizer
compositions and excellent miscibility with liquid urea containing
fertilizer formulations, which may contain water. Another advantage
is their low cost.
Other Optional Components
[0023] Other optional components may be used in compositions of the
present invention. Examples of other agents, include but are not
limited to a nitrification inhibitor, a conditioner, xanthan gum,
calcium carbonate (agricultural lime) in its various forms for
adding weight and/or raising the pH of acidic soils; metal
containing compounds and minerals such as gypsum, metal silicates
and chelates of various micronutrient metals such as iron, zinc and
manganese; talc; elemental sulfur; activated carbon, which may act
as a "safener" to protect against potentially harmful chemicals in
the soil; a plant protectant; a nutrient stabilizer, super
absorbent polymers, wicking agents, wetting agents, plant
stimulants to accelerate growth, an inorganic nitrogen, phosphorus,
potassium (N-P-K) type fertilizer, sources of phosphorus, sources
of potassium, and organic fertilizers, surfactants, such as
alkylaryl polyether alcohols; initiators, stabilizers, cross
linkers, antioxidants, UV stabilizers, reducing agents, dyes, such
as blue dye (FD & C blue #1); and plasticizers. Examples of
conditioners include but are not limited to tricalcium phosphate,
sodium bicarbonate, sodium ferricyanide, potassium ferricyanide,
bone phosphate, sodium silicate, silicon dioxide, calcium silicate,
talcum powder, bentonite, calcium aluminum silicate, stearic acid,
and polyacrylate powder. Examples of plant protectants and nutrient
stabilizers include silicon dioxide, and the like.
[0024] Nitrification inhibitors are compounds which inhibit the
conversion of ammonium to nitrate and reduce nitrogen losses in the
soil. Examples of nitrification inhibitors include, but are not
limited to, dicyandiamide (DCD), and the like. The DCD of the
present invention can have a particle size in the range from about
50 to 350 .mu.m.
[0025] The content of the additional components can be from about 1
to about 99 percent by weight of the composition. For example, the
amount of the additional components in the composition can be about
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,
54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70,
71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87,
88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98 or about 99% by weight
of the total granular fertilizer composition. If DCD is present it
may be in the range of about 40 to 95. The ratio of NBPT to DCD
should exceed a value of about 0.02, in some embodiments is between
about 0.02 and about 10,0, and in some embodiments is between about
0.04 and about 4.0.
[0026] The utilization of both a urease inhibitor and a
nitrification inhibitor, in the fertilizer composition of this
invention offers an opportunity to tailor the make-up of the
composition to match the nitrogen nutrient demand of a given
crop/soil/weather scenario. For example, if the soil is
characterized by a low pH and/or if rain is anticipated shortly
after fertilizer application and the opportunity for ammonia losses
through volatilization to the atmosphere is thereby diminished, the
level of the NBPT urease inhibitor incorporated into the
formulation may be reduced, within the specified range, without
also changing the level of the DCD nitrification inhibitor. The
relative resistance of the fluid fertilizer composition of this
invention to urea hydrolysis and ammonia oxidation is controlled by
properly selecting the NBPT to DCD weight ratio of the composition.
This ratio should exceed a value of about 0.01, or between about
0.02 and about 8.0, or be between about 0,05 and about 1.0. Fluid
fertilizer compositions with NBPT to DCD weight ratios near the
higher end of these ranges will exhibit relatively higher
resistance to urea hydrolysis than to ammonium oxidation, and vice
versa.
Compositions with UFP
[0027] Another object of the present invention is the use of the
liquid composition containing the phosphoric or thiophosphoric
triamide derivative in compositions that can be used in
urea-containing fertilizers. In some applications, a UFP has been
used as a carrier for NBPT (see e.g. U.S. Patent Publication
2007/0157689). Accordingly, in another group of embodiments, the
solutions of the present invention are suitable for deposited the
NBPT into the UFP.
[0028] The solid UFP of the present invention can be any form of
UFP. Examples of solid UFP include PERGOPAK M.RTM. 2, available
from Albemarle Corporation and NITAMIN 36S, available from Koch
Agronomic Services, LLC. The solid UFP is present in the
composition in the range of about 3 to 80%.
[0029] The means by which the NBPT and aryl alkyl alcohol
composition is deposited onto the UFP can be selected from any
method known. In one group of embodiments, the one or more active
agents are deposited onto the UFP by using a drying device such as
a high shear mixer, ribbon drier, blade drier, or other similar
device. In one group of embodiments, the drying device is a ribbon
drier or blade drier.
[0030] Typically, one or more active agents are coated onto the UFP
by introducing into the drying device the UFP and a solution
comprising NBPT and aryl alkyl alcohol.
[0031] The amount of UFP used may vary and will usually depend on
the particular application, as well as the optional presence of
other components besides the UFP used in the present invention. The
solution comprising NBPT and aryl alkyl alcohol typically contains
from about 20 to 60 wt. % of the NBPT, based on the weight of the
solution, of the one or more active agent(s). In one group of
embodiments, the solution comprises from about 25 to 50 wt. %,
based on the total weight of the composition. In one group of
embodiments, the solution comprises from about 30 to about 35 wt. %
of the active agent based on the total weight of the composition.
In a further embodiment of the invention, the composition contains
from about 1 to 55% UFP and from about 99.0 to 70.0% DCD. Without
DCD, the composition may contain about 1 to 80% NBPT and about 99
to 20% UFP.
[0032] In the practice of this embodiment of the present invention,
the UFP and the NBPT and aryl alkyl alcohol solution can be
introduced into the drying device simultaneously, in stages, either
the UFP or the NBPT and aryl alkyl alcohol solution can be
introduced before the other, or any combinations thereof. Thus,
this embodiment of the present invention can be either a batch or
continuous process. In one group of embodiments, the NBPT and aryl
alkyl alcohol solution is introduced into the drying device after
the UFP. In this and other embodiments, the introduction of the
active agent solution is controlled to avoid over-wetting of the
UFP. Over-wetting can be prevented by introducing the active agent
solution into the drying device at a rate substantially equal to
the rate at which the solvent volatilizes. The volatilization of
the solvent is achieved by operating the drying device under
conditions that include a temperature that is below the melting
point of the active agent(s) and below the boiling point of the
solvent. In one group of embodiments, the drying device is operated
under such a temperature and a sub-atmospheric pressure. In one
group of embodiments, the temperatures under which the drying
device is operated are in the range of from about 20.degree. C., to
about 200.degree. C., or in the range of from about 20.degree. C.
to about 100.degree. C., or from about 20.degree. C. to about
50.degree. C. Also, as stated above, the drying device may be
operated under sub-atmospheric pressures, i.e. under a vacuum.
These pressures may be in the range of from about 760 mmHg to about
0.1 mmHg, or in the range of from about 500 mmHg to about 50 mmHg,
or from about 100 mmHg to about 50 mmHg.
Fertilizer Compositions
[0033] The resulting solid is then blended directly with granulated
urea or be used as an additive to liquid urea.
Solid Urea-Based Fertilizer Compositions
Urea Fertilizer Base
[0034] The urea-based granular fertilizer of the present invention
can include any suitable quantity of a urea source and contains one
or more additional components. In one group of embodiments, the
urea source is granulated solid or prilled urea. One of skill in
the art will appreciate other urea sources for the inventive
methods. The amount of the urea source in the urea-based granular
fertilizer can range from about 1% to about 99% by weight of the
total granular fertilizer composition. The amount of the urea
source in the urea-based granular fertilizer can be about 1, 2, 3,
4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,
22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55,
56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72,
73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89,
90, 91, 92, 93, 94, 95, 96, 97, 98 or about 99% or more by weight
of the total granular fertilizer composition.
[0035] In another group of embodiments, the present invention
provides a urea-based granular fertilizer composition comprising:
[0036] a) a urea source of from about 95% to 99.075% by weight of
the total granular fertilizer composition; [0037] b) a composition
of NBPT and aryl alkyl alcohol as described above in the range of
from about 0.025% to 5% by weight of the total granular fertilizer
composition.
[0038] Thus in one embodiment, the urea content of the composition
of this invention is between about 90% and about 99% by weight, and
alternatively between about 92% and about 99% by weight, The
content of the NBPT composition is between about 0.02% and about
0.5% by weight, or between about 0,04% and about 0.4% by weight.
DCD may account for about 0,01% to about 1.2% by weight of the
composition, and in some embodiment's accounts for between about
0.05% and about 1,1% by weight of the composition. The composition
may also contain some moisture, urea synthesis byproducts, and an
aryl alkyl alcohol, and as noted above may optionally contain other
additives, such as a dye, an NBPT stabilizer, or a micronutrient.
The diameter of the granules of the improved homogenous urea-based
fertilizer composition of this invention ranges from about 0.5
millimeters to about 10 millimeters, and in some embodiments from
about 0.8 millimeters to about 0.9, to about 1.0, to about 1.1, to
about 1.2, to about 1,3, to about 1.4, to about 1.5, to about 1.6,
to about 1.7, to about 1.8, to about 1.9, to about 2.0, to about
2.1, to about 2.2, to about 2.3, to about 2.4, to about 2.5, to
about 2.6, to about 2.7, to about 2.8, to about 2.9, to about 3.0,
to about 3.1, to about 3.2, to about 3.3, to about 3.4, to about
3.5, to about 3.6, to about 3.7, to about 3,8, to about 3.9, to
about 4.0, to about 4.1, to about 4,2, to about 4.3, to about 4.4,
to about 4.5, to about 4.6, to about 4.7, and to about 4,8
millimeters
Processes for Making Solid Urea-Based Fertilizer Compositions
[0039] In one aspect, the present invention provides a method,
wherein the NBPT composition is blended or mixed with the urea. The
conditioner when mixed or blended with a urea-based fertilizer
provides a urea-based fertilizer that has improved storage and
handling properties.
[0040] In one group of embodiments, the present invention provides
a composition similar to wherein commercial fertilizers, including,
but not limited to SUPER U.RTM.; FLEXX.RTM.; UMAXX.RTM.; or
granular urea treated with AGROTAIN DRY.RTM..
[0041] In one group of embodiments, the NBPT and UFP composition
can incorporated into the homogenous urea-based fertilizer
composition by blending, either dry or as a concentrated solution
of NBPT and UFP in an aryl alkyl alcohol solvent on urea. The
incorporation can be done at ambient conditions or on molten urea
at a temperature of about 266.degree. F. to about 275.degree. F.
prior to the granulation or prilling of the urea in a conventional
urea production facility. Sufficient mixing is employed during this
blending step to assure that the NBPT, UFP and aryl alkyl alcohol
solution is homogeneously distributed, especially before the melt
cools and solidifies in the subsequent granulation step if molten
urea is used.
[0042] The NBPT, UFP and aryl alkyl alcohol solution of this
invention remains stable over extended periods of time and over
temperatures ranging from about 30.degree. F. to about 120.degree.
F. Thus, both the solid and liquid forms of the NBPT and UFP
composition of this invention can be managed using conventional
storage, transportation, and pumping equipment.
[0043] The amount of NBPT and UFP compositions of the present
invention added to urea in accordance with this invention in either
solid or liquid form depends on the desired NBPT content of the
granular fertilizer composition and can be readily calculated by
those skilled in the art. In some embodiments, no or only very
limited quantities of aryl alkyl alcohol are introduced into the
urea along with the NBPT and UFP. For example, if the NBPT and UFP
content of the NBPT, UFP and aryl alkyl alcohol solution used to
incorporate the NBPT and UFP in the fertilizer composition is 70%
and the NBPT content of the resulting fertilizer composition is
0.07%.
[0044] In some embodiments, DCD can also be added to and blended
with the urea at this point in the formulation rather than during
the formulation with the UFP. Several methods can be used for the
introduction of DCD into solid or molten urea: if available as a
powder or in granular form, the DCD can be fed into a stream of
solid or molten urea using a conventional solids feeding device;
or, the DCD may be dissolved in a relatively small quantity of
molten urea, as for example in a side stream of molten urea in a
urea plant, to form a concentrated DCD solution in molten urea
which is then metered into the main stream of the solid or molten
urea. Finally, the DCD may be incorporated into the NBPT, UFP and
aryl alkyl alcohol solution described hereinabove and introduced
into the urea or molten urea along with the NBPT, UFP and aryl
alkyl alcohol solution. Regardless of the method selected to
introduce the DCD into the urea, sufficient mixing should be
provided to facilitate homogenous distribution of the DCD
throughout the urea. The homogeneous distribution of the NBPT, the
UFP and DCD in the granular fertilizer compositions of this
invention enhances the performance of these compositions in terms
of their ability to promote plant growth.
[0045] The order in which the NBPT and UFP composition and the DCD
are added to the urea in the practice of this invention is
flexible: either the NBPT and UFP composition or DCD may be
introduced first, or both of these components may be added
simultaneously. In one group of embodiments, the DCD is added first
to provide adequate time for both the dissolution and uniform
distribution of the DCD in the molten urea prior to the granulation
step. A convenient point for the addition of DCD to urea in a urea
production plant is before or between any evaporation steps used to
reduce the water content of the urea. The NBPT and UFP composition,
however, may be introduced into the molten urea just prior to the
granulation or prilling step with only sufficient retention time in
the melt to allow for uniform distribution of the NBPT in the melt.
In one group of embodiments, the retention time of the melt between
the point of the NBPT and UFP composition addition arid the
granulation step is less than 5 minutes, or less than 1 minute.
[0046] After the NBPT and UFP composition is combined with the
urea, the granules may be sized. In one group of embodiments,
granules which pass through a 4 mesh Tyler Series sieve (about 4.76
millimeters) and stay on a 20 mesh Tyler Series sieve (about 0.84
millimeters) are retained as product. The undersized particles may
he recycled and the oversized particles may be ground and/or
recycled.
Liquid Urea-Based Compositions
[0047] The present invention also provides an improved fluid
urea-ammonium nitrate (UAN) fertilizer composition containing the
NBPT composition. Specifically, the improved fluid fertilizer
composition of this invention is comprised primarily of an aqueous
solution of urea, ammonium nitrate, and the NBPT composition, and
optionally dicyandiamide (DCD).
[0048] The urea content of the composition of this invention is
between about 24% and about 32% by weight, or between about 26% and
about 32% by weight; the ammonium nitrate content of the
composition is between about 34% and about 42% by weight, or
between about 36% and about 42% by weight; the NBPT content of the
composition is between about 0.01% and about 0.4% by weight, or
between about 0.02% and about 0.3% by weight; and the DCD accounts
for about 0% to about 2,0% by weight of the composition, and may
account for between about 0.03% and about 1,5% by weight of the
composition. The balance of the composition consists primarily of
water. An aryl alkyl alcohol solvent for the NBPT as disclosed
above, may also be present in small quantities.
Processes for Making Liquid Urea-Based Compositions
[0049] In accordance with the present invention, the NBPT
composition may be incorporated into the fluid fertilizer
composition by adding a solid or liquid form of the NBPT
composition directly to a UAN fluid with sufficient mixing to
assure that the NBPT is homogeneously distributed throughout the
fluid fertilizer composition. Both the solid and liquid forms of
the NBPT composition as disclosed above can be introduced into UAN
using conventional metering devices.
[0050] The amount of the NBPT composition in accordance with this
invention depends on the desired NBPT content of the fertilizer
composition within the ranges specified hereinabove and on the
NBPT, and aryl alkyl alcohol solution, and can be readily
calculated by those skilled in the art.
[0051] Like the solid formulation, DCD can also be added to the UAN
fluid at this stage, rather than with the UFP, alone. Several
methods are available for the introduction of DCD into UAN. If
available as a powder or in granular form, the DCD can be fed into
UAN fluid using a conventional solids feeding device. In one group
of embodiments, however, the DCD is first incorporated into a
relatively small quantity of UAN fluid so as to form a slurry of
DCD in UAN fluid; this slurry is then blended with the balance of
the UAN fluid in the amount needed to provide the desired
concentration of DCD within the ranges specified hereinabove.
Regardless of the method selected to introduce the DCD into the UAN
fluid, sufficient mixing should be provided to facilitate
homogenous distribution of the DCD throughout the UAN fluid. The
homogeneous distribution of both the NBPT composition and DCD in
the fluid fertilizer compositions of this invention enhances the
performance of these compositions in terms of their ability to
promote plant growth.
[0052] The order in which the NBPT composition and DCD are added to
the fluid fertilizer in the practice of this invention is flexible:
either the NBPT composition or DCD may be introduced first, or both
of these components may be added simultaneously. However, in light
of the relative instability of NBPT in aqueous solutions, solid or
liquid forms of the NBPT composition may be introduced into the
fluid fertilizer relatively late in production-storage-distribution
sequence of the fluid fertilizer, so as to minimize the time span
between the addition of the NBPT composition to the fluid
fertilizer and the application of the fertilizer to the soil.
[0053] The NBPT composition is added to the UAN solution in the
range of about 0.01 to 5.0% additive in the final product. In one
group of embodiments, the NBPT composition is added in the range of
about 0.4 to 2.5% to fluid UAN or urea solution, or blends thereof,
to form a fluid fertilizer. The fluid urea-based fertilizer of the
present invention contains from about 0.004 to 1.50% NBPT, from
about 0 to 0.850% DCD, and from about 99.9 to 97.0% aqueous UAN.
Optionally, the fertilizer can contain up to about 0.03% silicon
dioxide. The aqueous UAN contains urea and ammonium nitrate in
concentration ranges of about 15 to 50%. In one group of
embodiments, the range is from about 25 to 40%.
Use
[0054] The granular fertilizer composition of this invention made
by the methods described herein can be used in all agricultural
applications in which granular fertilizer compositions are
currently used. These applications include a very wide range of
crop and turf species, tillage systems, and fertilizer placement
methods. The fertilizer granules made with the NBPT composition of
present invention are useful for fertilizing a wide variety of
seeds and plants, including seeds used to grow crops for human
consumption, for silage, or for other agricultural uses. Indeed,
virtually any seed or plant can be treated in accordance with the
present invention using the compositions of the present invention,
such as cereals, vegetables, ornamentals, conifers, coffee, turf
grasses, forages and fruits, including citrus. Plants that can be
treated include grains such as barley, oats and corn, sunflower,
sugar beets, rape, safflower, flax, canary grass, tomatoes, cotton
seed, peanuts, soybean, wheat, rice, alfalfa, sorghum, bean, sugar
cane, broccoli, cabbage and carrot.
[0055] The granular urea-based fertilizer composition of this
invention can be used in all agricultural applications in which
granular urea is currently used. These applications include a very
wide range of crop and turf species, tillage systems, and
fertilizer placement methods. The new improved composition
increases the nitrogen uptake by plants, enhances crop yields, and
minimizes the loss of both ammonium nitrogen and nitrate nitrogen
from the soil.
[0056] The rate at which the fertilizer composition of this
invention is applied to the soil may be identical to the rate at
which urea is currently used for a given application in the case of
the composition of this invention. Alternately, the composition of
this invention may be applied to the soil at lower rates than is
the case for urea. It is of interest to illustrate the quantities
of NBPT and DCD introduced into the soil when a given composition
of this invention is applied as a fertilizer. For example, assuming
that the composition is applied to the soil at a rate of 100 pounds
per acre and that it contains 0.1% NBPT and 1% DCD, it can be
readily calculated that the rates of NBPT and DCD application are
0.1 and 1.0 pounds per acre, respectively.
[0057] The UAN-based fertilizer composition of this invention can
be used in all agricultural applications in which UAN is currently
used. These applications include a very wide range of crop and turf
species, tillage systems, and fertilizer placement methods. The
fertilizer composition of this invention can be applied to a field
crop, such as corn or wheat, in a single surface application and
will nevertheless supply sufficient nitrogen to the plants
throughout their growth and maturing cycles.
[0058] The rate at which the fertilizer composition of this
invention is applied to the soil may be identical to the rate at
which UAN is currently used for a given application. Alternately,
the composition of this invention may be applied to the soil at
lower rates than is the case for UAN and still provide comparable
crop yields, but with a much lower potential for nitrogen loss to
the environment. It is of interest to illustrate the quantities of
NBPT and DCD introduced into the soil when a given composition of
this invention is applied as a fertilizer. For example, assuming
that the composition is applied to the soil at a rate of 200 pounds
per acre and that it contains 0.05% NBPT and 0.5% DCD, it can be
readily calculated that the rates of NBPT and DCD application are
0.1 and 1.0 pounds per acre, respectively.
[0059] The following examples are intended to illustrate, but not
to limit, the methods and compositions of the invention. All
percentages described herein are by weight, unless otherwise
indicated.
EXAMPLES
[0060] The following describes examples of compositions of NBPT of
the present invention. The compositions are prepared by dissolving
at least 25 wt. % of NBPT in the following solvents with stirring
to form clear solutions. The dissolution of example 3 proceeded
easily.
Example 1
[0061] A concentrated solution of N-(n-butyl)thiophosphoric
triamide (NBPT) was prepared according to the following: Molten
commercial NBPT (63.6 g, .about.84% NBPT) was added to benzyl
alcohol (118.11 g) and the resulting liquid was shaken for 30
seconds and allowed to cool to rt. The NBPT concentration of this
solution was approximately 29%.
Example 2
[0062] To the NBPT solution from Example 1 was added propylene
glycol (17.84 g) to give a final NBPT concentration of 26.7% and a
green dye (0.448 g) and the mixture was stirred at rt until
complete dissolution of the dye (.about.10 min).
Example 3
[0063] Molten commercial NBPT (16 g, .about.84% NBPT) was added to
warmed (40.degree. C.) benzyl alcohol (34 g) and the resulting
liquid was shaken for 30 seconds and allowed to cool to rt. The
NBPT concentration of this solution was approximately 26.7%.
Example 4
[0064] A concentrated solution of N-(n-butyl)thiophosphoric
triamide (NBPT) was prepared according to the following: Molten
commercial NBPT (54.5 g, >97% NBPT) was added to benzyl alcohol
(130.87 g) and the resulting liquid was shaken for 30 seconds and
allowed to cool to rt. The NBPT concentration of this solution was
approximately 29%.
Example 5
[0065] Molten commercial NBPT (13.4 g, .about.97, NBPT) was added
to warmed (40.degree. C.) benzyl alcohol (36.6 g) and the resulting
liquid was shaken for 30 seconds and allowed to cool to rt. The
NBPT concentration of this solution was approximately 26.7%.
Urea Coating
Example 6
[0066] To 100 g of urea was added 0.34 g of the NBPT solution from
Example 2 in a sealable cup. The lid was securely fastened and the
mixture was shaken for 1 min. The resulting urea was uniformly
coated with the NBPT as indicated by the uniformity of the green
dye covering the urea.
Example 7
[0067] To 100 g of urea was added 0.34 g of the NBPT solution from
Example 4 in a sealable cup. The lid was securely fastened and the
mixture was shaken for 1 min. The resulting urea was uniformly
coated with the NBPT as indicated by the uniformity of the green
dye covering the urea.
Example 8
[0068] The stability and the capability of the solutions of
N-(n-butyl)thiophosphoric triamide (NBPT) in the solvent systems of
the present invention to remain liquid at low temperatures
(flowability) is assessed. A 26.7 wt. % solution of NBPT in the
binary solution of Example 2 is stored for 3 months at 0.degree. C.
and the presence of crystals in the solutions and the flowability
of the solutions is assessed.
[0069] For comparison with the prior art, a mixture containing
propylene glycol (PG) with 10 Wt. % N-methylpyrrolidone (NMP)
described in the U.S. Pat. No. 5,698,003 and a mixture containing
90 wt. % dipropylene glycol monomethyl ether with 10 wt. %
N-methylpyrrolidone (NMP) described in WO 2008000196 was used. The
following observations were made: The mixture of U.S. Pat. No.
5,698,003 crystallized under said conditions. While the mixture of
the present invention and of WO 2008000196 did not crystalize under
said conditions, the binary solution of the present contained no
polyvinylpyrrolidone or NMP, surprisingly showing that the addition
of crystallization inhibitors is not necessary. Other binary and
ternary solvent systems of the present invention have similar
properties. All solvent systems of the present invention are
water-miscible.
Example 9
[0070] A highly stable solution of N-(n-butyl)thiophosphoric
triamide (NBPT) is a key feature for its use and long-term storage
of its solutions. The presence of water causes the decomposition of
NBPT into noneffective substances during a longer storage and is
the main cause of the NBPT degradation during a long-term
storage.
[0071] The solvent systems of the present invention show a
stabilizing effect towards NBPT. All solvents used in this example
are commercially available in a very good quality, having the water
content lower than 0.1 wt. %. Nevertheless, to confirm the
stabilization effect of the solvents, the water content was
artificially increased to 1 wt. %. The thus adjusted solvent
systems simulate the effect of the moisture on NBPT (higher
contents of the moisture than 1 wt. % are uncommon).
[0072] In order to verify the long-term stability of NBPT, the
following solvents containing less than 0.1 wt. % of water were
tested. 20 wt. % solutions of NBPT were stored at room temperature
at daylight in glass, well-sealed vials. The monitoring of any
degradation NBPT was carded out by reverse-phase HPLC with UV
detection in the mobile phase containing 25 vol. % acetonitrile and
75 vol. % 0.005M ammonium acetate. The chromatogram was evaluated
at the wavelength of 193 nm. The mobile phase flow was 1 ml/min,
the column temperature was 40.degree. C. The injected volume was 5
.mu.l. The evaluation was carried out by the method of external
standard with the calibration using a calibration line. RSD is the
relative deviation in rel. %, calculated from three repeats of
sampling and two repeats of analysis of each sample.
[0073] The solvent systems of the present invention have a
stabilizing effect towards NBPT. After 12 weeks of storage, no
significant decrease of the content of the active component NBPT
occurred in any sample (the method used can determine the change of
approx. at least 1 wt. %).
Example 10
[0074] Granular Urea formulation with Formulation of EXAMPLE 6
[0075] As a first step, a 121,000 lb. batch of NBPT solution of
Example 1 was pumped at a rate equivalent to 4 pounds of NBPT per
1996 pounds of urea into a 34 ton/hour stream of molten urea
passing through a pipe leading from the last stage of urea
evaporation directly to the urea granulation apparatus in a urea
production facility. The temperature of the molten urea at the
point at which the NBPT solution was injected was about 275.degree.
F. Although the retention time of the urea stream between the point
at which the concentrated NBPT solution was injected and the urea
granulation apparatus was only in the order of 20 seconds, the
degree of turbulence in the stream of molten urea assured thorough
mixing and homogenous distribution of the concentrated NBPT
solution in the molten urea. The urea production facility was
operated in this mode for a period of about 8.5 days, during which
time about 6960 tons of urea containing 0.2% NBPT was produced. The
fertilizer was tested for the uniformity of distribution of NBPT.
The NBPT was uniformly distributed through each granule of the
product.
Example 11
[0076] Liquid Urea Formulation with Liquid Formulation of NBPT
[0077] This example illustrates the method of this invention for
the incorporation of the NBPT composition into a fluid
urea-containing fertilizer composition. The formulation of Example
1 was added at a rate equivalent to 2 pounds of NBPT per 1998
pounds of UAN solution into a 50 ton/hour stream of UAN solution
containing 30% urea and 40% ammonium nitrate and approximately 10
pounds per ton DCD. Said stream of hAN solution was being
transferred from a liquid storage tank into liquid rail cars.
Although the retention time of the UAN solution between the point
near the liquid storage tank at which the concentrated NBPT
solution was injected into the UAN solution and the point at which
the solution was discharged into the rail car was only in the order
of 40 seconds, the degree of turbulence in the stream of UAN
solution assured thorough mixing and homogenous distribution of the
concentrated NBPT solution in the UAN solution. A set of rail cars
was filled in this manner with a total of about 1400 tons of UAN
solution containing about 0.1% NBPT.
Example 12
[0078] Granular Urea Formation with EXAMPLE
[0079] This example illustrates the method of this invention for
the incorporation of the NBPT composition into a granular
urea-containing fertilizer composition. The test was conducted in
an industrial facility with a urea production rate of 34 tons per
hour. DCD was introduced into the molten urea at a rate of 20
pounds of DCD per 1976 pounds of urea before the last stage of
evaporation that is at a point in the continuous urea scheme where
the molten urea has a moisture content of about 4-6%. Thourough
mixing was provided to assure homogeneous distribution of the DCD
in the urea melt. The DCD containing molten urea then passes
through the last evaporator to reduce its moisture content to about
1%. A concentrated NBPT solution of Example 1 was pumped into the
DCD-containing molten urea stream at a rate equivalent to 4 pounds
NBPT per 1996 pounds of DCD-containing molten urea. The temperature
of the molten urea at the point at which the NBPT solution was
injected was about 275.degree. F. The resulting stream of NBPT- and
DCD-containing molten urea was next directed through a pipe leading
directly to the granulation apparatus in a urea production
facility. Although the retention time of the NBPT- and
DCD-containing molten urea stream between the point at which the
concentrated NBPT solution was injected and the urea granulation
apparatus was only in the order of 20 seconds, the degree of
turbulence in the stream of molten urea composition assured
thorough mixing and homogenous distribution of the concentrated
NBPT solution in the DCD-containing molten urea.
[0080] The solutions of N-(alkyl)phosphoric or thiophosphoric
triamides in the solvent systems of the present invention can be
long-term stored, used for the impregnation of solid
urea-containing fertilizers, such as granular urea, added into the
mixture for the manufacture of solid urea-containing fertilizers or
added into liquid urea-containing fertilizers. They can also be
used as a suitable urease inhibitor formulation for addition into
animal wastes or sprays masking urine odor.
[0081] Although the foregoing invention has been described in some
detail by way of illustration and example for purposes of clarity
of understanding, one of skill in the art will appreciate that
certain changes and modifications may be practiced within the scope
of the appended claims. In addition, each reference provided herein
is incorporated by reference in its entirety to the same extent as
if each reference was individually incorporated by reference. Where
a conflict exists between the instant application and a reference
provided herein, the instant application shall dominate.
* * * * *