esterified alkyl polyglucosides as wetting agents for plant growth media
TRANSCRIPT
Esterified Alkyl Polyglucosides as
Wetting Agents for Plant Growth Media
PRESENTATION OVERVIEW
I. Introduction- APG Ester Chemistry
- Demand for Irrigation Surfactants & Prior Discoveries
II. Materials and Methods- Saturation Test
- Mini-Disk Infiltrometer (MDI) Evaluations
III. Infiltration Results
IV. Conclusions and Future Outlook
Organic Chemistry of Esters
Carboxylic acid derivatives in which hydroxyl group
(-OH) is replaced by an alkoxy group (-OR)
R—C—OH + R’—OH R—C—O—R’ + H2O
Esterification:OO
ACID ALCOHOL ESTER
Synthesis of Alkyl Polyglucosides
OO
OOHH
OOHHOOHH
OOHHOOHH HHOO
OOOOHH
OOHHOOHH
OOOOHH
OOHHOOHH
OOHH
OO
OO
-- HH22OO
HH++
nn
nnmm
++
GLUCOSE FATTY
ALCOHOL
ALKYL POLYGLUCOSIDE
1) Maleic Anhydride
2) Sodium Sulfite
1) Citric Acid
2) Sodium Hydroxide
1) Tartaric Acid
2) Sodium Hydroxide
Alkylpolyglucoside Alkylpolyglucoside
SulfosuccinateSulfosuccinate
OOHH
++
OOOOHH
OOHHOOHH
OOOOHH
OOHHOOHH
OO
OO
nnmm
Alkylpolyglucoside
Synthesis of Alkyl Polyglucoside Esters (AGEs)
Alkylpolyglucoside Alkylpolyglucoside
CitrateCitrate
Alkylpolyglucoside Alkylpolyglucoside
TartrateTartrate
AGEs Retain Favorable APG Properties…
Derived from
natural, renewable
raw materials
Strong biological
performance as
built-in and tank mix
adjuvants
Biodegradable, not
harmful to the
environment
Free from dioxane,
ethylene oxide, and
nitrosamine
precursors
Mild to skin and non-
irritating to the eyes
PATENT PENDINGAGEs Offer Unique Efficacy
ISAA 2007
ISAA 2010
Surfactant Functions in Agrochemicals
• Emulsification
• Dispersion
• Dissolution
• Foaming
• Adhesion Promotion
• Viscosity Modification
• Wetting/Waterproofing
Surfactants can modify the
characteristics of
environmental interfaces
and agrochemical
preparations.
Adsorption at interfaces
affects emulsification,
dispersion, foaming, and
wetting.
Micellar aggregation in the
solution phase affects
dissolution of solvent-
insoluble material and can
alter viscosity.
Water use efficiency and conservation are essential for the
sustainable and profitable production of horticultural and
agricultural crops.
Excessive irrigation can be equally
detrimental: leading to increased erosion,
run-off, nutrient leaching, disease
susceptibility, and resource costs.
The Importance of Irrigation Efficiency
The slightest water deficits can impact
crop yield and quality.
Mechanical Advances Are Part of the Solution
Allow growers to control
timing, duration, and
uniformity of water
applied to the plant and
soil surface.
Unable to control delivery
of applied water below the
surface and into the root
zone, where many
agronomic and economic
benefits are realized.
The Need for Media Wetting Agents
Media surface properties can vary considerably and may not
allow favorable interactions with irrigation water.
DRY
SATURATED
The Need for Media Wetting Agents
Plant growth media may naturally resist hydration,
especially at low moisture contents, inhibiting
uniform percolation.
The Need for Media Wetting Agents
Once hydrated,
media may not dry down and re-wet uniformly.
Requirements of a Growing Medium
• To provide anchorage for the plant
• To provide adequate air spaces for root respiration
• To hold sufficient available water
• To hold sufficient available nutrients
• To be free of plant pathogens, pests, and weeds
• To be safe when handled by people
Irrigation Surfactant Development
new technologies
new approaches
new materials
There is an ongoing
need for new
technologies with
superior
performance and
environmental
profiles.
Prior Discoveries
Kostka and Bially, 2005 (US 6,851,219*).
The Hydrophilicity of Water Repellent Soil.PEO/PPO Block Copolymer + Nonionic APG Synergism
Kostka and Bially, 2009 (US 7,541,386*).
Wetting of Water Repellent Soil by Low HLB
EO/PO Block Copolymers...
* Intellectual property of Aquatrols Corp (Paulsboro, NJ, USA)
Coconut Fiber Medium (Coir)
•Coir pith available in large quantities as by-product of the coconut industry
•Contains equal portions of lignin and cellulose and is rich in potassium and micronutrients
•Low Cation Exchange Capacity (CEC); does not retain cations or buffer pH well
•Favored for high water holding capacity; improves moisture retention, infiltration rate, total porosity, and hydraulic conductivity of soils
Coconut Fiber Medium (Coir)
Moisture Content Monitoring
Saturation Test Method
UNTREATED TREATED
70 85 100 100 110
170 185 190
360
Time (s) to Saturate 2g of
Air-Dried Coir (10% VWC, 3000mgL-1)
Mini Disk Infiltrometer (MDI)•Measures hydraulic conductivity and infiltration
rate of the medium it is placed upon.
•Can also be used to measure soil water repellency
index and evaluate wetting agent efficacy.
Property of Decagon Devices, 2007.
bottom view
Mini Disk Infiltrometer (MDI)
Infiltration = I = C1t + C2√t
Hydraulic Conductivity = k = C1/A
where C1
is the slope of the curve of
cumulative infiltration vs square root of time
and A = 11.65(n0.1-1)exp [2.92(n-1.9)αh0]
(αr0)0.91
related to soil parameters
Property of Decagon Devices, 2007.
0
0.13
0.25
0.38
0.57
0.69
0.82
0
0.5
1
0 5 10 15
Cu
mu
lati
ve
In
filt
rati
on
(cm
)
Square Root of Time
Water Infiltration Rate into Coir
Coir (36% VWC)
Coir (18% VWC)
Coir (10% VWC)
y= 0.0619x – 0.1195
Hydraulic Conductivity = k = C1/A
Water Infiltration Rate vs Media Moisture Content
36% VWC
(3.7 cm3/min)
18% VWC
(2.3 cm3/min)
10% VWC
(1.0 cm3/min)
0
5
10
30s 60s 90s 120s 150s 180s
0
5
10
30s 60s 90s 120s 150s 180s
0
5
10
30s 60s 90s 120s 150s 180s
Infi
ltra
tio
n V
olu
me
(cm
3)
Cumulative Infiltration (3000 mg/L)
30s
60s
90s0
0.5
1
1.5
2
2.5
3
Infi
ltra
tio
n V
olu
me
(cm
3)
30s
60s
90s0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
AGE-EC
500 mg/LAGE-ET
500 mg/LAGE-EC
50 mg/LAGE-EC
50 mg/LControl
Cumulative Infiltration (500, 50 mg/L)
Infi
ltra
tio
n V
olu
me
(cm
3)
Initial Wetting (IW) vs Re-wetting (RW)
30s
60s
90s0
1
2
3
4
5
6
Infi
ltra
tio
n V
olu
me
(cm
3)
Summary of Results
Saturation
Time (s)
90-Second Infiltration Volume
(cm3)
Treatment 3000mgL-1 3000mgL-1 500mgL-1 50mgL-1
Tartrate Ester 70 3 2 1
Citrate Ester 85 3 2 1
EO/PO Copolymer 100 2 1 1
APG (C12-14) 100 2 0 0
APG (C8-10) 110 1 0 0
APG (C8) 170 1 0 0
APG (C6) 185 1 0 0
Saponin 190 0 0 0
Control 360 0 0 0
Summary of Results
90-Second Infiltration
Volume (cm3)
Treatment 3000mgL-1 Re-Wet
Tartrate Ester 3 6
Citrate Ester 3 5
EO/PO Copolymer 2 4
APG (C12-14) 1 2
Saponin 0 2
Control 0 1
Conclusions and Future Outlook
• Performance advantages are apparent in the esterification of nonionic APGs.
• Anionic APG esters can be highly effective at delivering irrigation water and agrochemicals to the root zone of crops growing in difficult-to-wet plant growth media.
• Patent pending. Research is underway to further investigate these properties.