esterified alkyl polyglucosides as wetting agents for plant growth media

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.