Cartap

1.Chemical and Physical Properties

1.1 Chemical Identity

• Common Name: Cartap Hydrochloride
• Chemical Name (IUPAC): S,S′-[2-(dimethylamino)propane-1,3-diyl] dicarbamothioate hydrochloride
  • Or: 1,3-Bis(carbamoylthio)-2-(N,N-dimethylamino)propane hydrochloride
• CAS Registry Number:
  • Cartap Hydrochloride: 22042-59-7 (or 15263-52-2 for some registrations)
  • Cartap (free base): 15263-53-3
• Chemical Class: Nereistoxin analogue insecticide. Derived from nereistoxin, a natural toxin isolated from the marine annelid Lumbriconereis heteropoda.
• Molecular Formula: C₇H₁₅N₃O₂S₂·HCl (for hydrochloride)
• Molecular Weight: 273.8 g/mol (for hydrochloride)

1.2 Key Physical Properties (Cartap Hydrochloride)

• Appearance:
  • White or slightly yellowish crystalline powder or solid.
• Odour:
  • Slight, characteristic amine-like odour or almost odourless.
• Melting Point:
  • Typically 179-181°C (decomposes). Some sources cite slightly different ranges (e.g., 183-185°C dec.).
• Solubility:
  • Water: Highly soluble (approx. 200 g/L at 25°C).
  • Organic Solvents (at 25°C):
    • Methanol: Soluble (e.g., ~20 g/L)
    • Ethanol: Slightly soluble
    • Acetone, Diethyl ether, Benzene, Chloroform, n-Hexane: Practically insoluble or very slightly soluble.

1.3 Key Chemical Properties (Cartap Hydrochloride)

• Stability:
  • Hydrolysis: Stable in neutral and acidic solutions. Hydrolyzes in alkaline solutions (e.g., pH > 9) to nereistoxin and other metabolites.
  • Photolysis: Moderately stable to light.
  • Thermal Stability: Relatively stable at room temperature but decomposes at its melting point.
• Acidity/Basicity (pKa):
  • Being a hydrochloride salt of a dimethylamine, it is acidic in solution. The free base Cartap has basic properties due to the tertiary amine group.

2.Production Technologies

2.1 Chemical Synthesis Overview (Cartap Hydrochloride)

• General Approach: The synthesis usually starts from 1,3-dichloro-2-propanol or related precursors. Key steps involve:
  • Amination to introduce the dimethylamino group.
  • Thiocarbamoylation (reaction with thiocyanates or thiourea derivatives followed by carbamoylation) to form the bis(carbamoylthio) groups.
  • Conversion to the hydrochloride salt.
• Starting Materials:
  • Common starting materials include 1,3-dichloro-2-propanol, dimethylamine, sodium thiocyanate (or potassium thiocyanate), and reagents for carbamoylation (e.g., phosgene followed by ammonia, or isocyanic acid derivatives).
• Key Considerations:
  • Control of reaction conditions to avoid side reactions and ensure good yield and purity. Proper handling of toxic intermediates like thiocyanates.

2.2 Technical Production Process

• Scale & Equipment:
  • Industrial synthesis involves batch reactors, separation equipment (filtration, centrifugation), drying units, and purification steps.
• Quality Control:
  • Technical grade Cartap Hydrochloride (typically >95-98% purity) is tested for active ingredient content, impurities, moisture content, and physical properties.
• Environmental Aspects:
  • Management of waste streams containing sulfur compounds and amine derivatives.

2.3 Formulation Technologies

• Common Types:
  • Soluble Powders (SP): Most common, typically 50% SP (e.g., 500 g/kg). Readily dissolves in water for spraying.
  • Granules (GR): For soil application, typically 2-5% GR.
  • Dustable Powders (DP): Less common now due to drift concerns.
  • Wettable Powders (WP): Occasionally found.
• Key Components:
  • Active ingredient (Cartap Hydrochloride), fillers (e.g., clay, kaolin for SP/GR), wetting agents, and dispersants (for WP).
• Purpose:
  • To provide a product that is stable, easy to handle and apply, and effective for specific target pests and application methods (e.g., foliar spray, soil incorporation). Mixtures with other insecticides or fungicides are less common for Cartap compared to some other active ingredients

3.Applications

3.1 Biological Mode of Action

• Mechanism:
  • Cartap itself is a pro-insecticide. It is converted in the insect body and environment to nereistoxin. Nereistoxin acts as a blocker of the nicotinic acetylcholine receptors (nAChRs) in the insect's central nervous system. It competitively inhibits acetylcholine, leading to paralysis and death of the insect.
• Effects:
  • Causes cessation of feeding, paralysis, and eventual death of susceptible insects. It has contact and stomach action.
• Selectivity:
  • Generally more toxic to chewing insects (Lepidoptera, Coleoptera larvae) and some sucking insects, than to many beneficial insects, though this can vary.

3.2 Agricultural Applications

• Crop Spectrum:
  • Widely used in rice (its primary market), sugarcane, potatoes, vegetables (e.g., cabbage, crucifers, onions, tea), fruits, and other crops.
• Pest Spectrum: Effective against a range of chewing and some sucking insect pests, including:
  • Lepidopteran larvae: Rice stem borers (e.g., Chilo suppressalis, Scirpophaga incertulas), rice leaf rollers, diamondback moth (Plutella xylostella), cabbage butterfly, armyworms.
  • Coleopteran pests: Colorado potato beetle, rice water weevil, some flea beetles.
  • Thysanoptera: Some thrips species.
• Application:
  • Primarily as a foliar spray (for SP formulations) or applied to soil/paddy water (for GR formulations). Timing is crucial, often targeting early larval stages.
• Resistance Management:
  • Resistance to nereistoxin analogues has been reported in some insect populations (e.g., diamondback moth). Rotation with insecticides having different modes of action is recommended.

3.3 Non-Agricultural Applications

• Limited Scope:
  • Primarily an agricultural insecticide. Non-agricultural uses are not widespread.
• Household/Public Health:
  • Not typically used for household pest control or public health vector control due to its toxicity profile and the availability of more suitable alternatives.

4.Market Analysis

4.1 Global Market Overview

• Market Size & Position:
  • A well-established insecticide, particularly significant in rice-growing regions of Asia (e.g., China, India, Vietnam, Japan, Southeast Asia). Global sales are substantial but smaller than leading broad-spectrum insecticides.
• Growth Trends:
  • Mature product. The market is relatively stable, with growth driven by rice production needs and its effectiveness against key rice pests. Generic production is widespread.
• Regional Demand:
  • Dominated by Asia-Pacific. Also used in parts of Latin America and Africa where rice and sugarcane are important crops.

4.2 Key Market Dynamics

• Drivers:
  • Cost-effectiveness, proven efficacy against major rice pests like stem borers, and relatively good fit in integrated pest management (IPM) programs for rice in some regions. Its systemic activity (when applied as granules) is an advantage.
• Restraints/Challenges:
  • Insect resistance in some key pests (e.g., diamondback moth), relatively high acute toxicity to mammals and non-target organisms (fish, bees if directly exposed), leading to regulatory scrutiny and restrictions in some countries. Competition from newer and potentially safer insecticides.

4.3 Competitive Landscape

• Original Developer:
  • Takeda Chemical Industries (Japan) first developed Cartap.
• Generic Market:
  • Many generic manufacturers, especially in China and India, produce and market Cartap Hydrochloride. This has led to significant price competition.
• Key Players:
  • Besides generic manufacturers, companies involved in rice agrochemicals often include Cartap in their portfolio for specific markets.

5.Upstream and Downstream Linkages

5.1 Upstream Linkages (Inputs for Production)

• Raw Materials:
  • Key chemical intermediates such as 1,3-dichloro-2-propanol (or related compounds), dimethylamine, sodium thiocyanate, and reagents for carbamoylation.
• Supply Chain:
  • Sourcing of intermediates often from specialized chemical manufacturers, with China and India being major suppliers of these basic chemicals.
• Technology & Equipment:
  • Requires standard chemical synthesis equipment including reactors, filtration units, dryers, and analytical tools for quality assurance.

5.2 Downstream Linkages (Outputs and Consumers)

• Primary Users:
  • Predominantly rice farmers. Also used by growers of sugarcane, vegetables, and other specified crops.
• Distribution Channels:
  • Agricultural input retailers, farmer cooperatives, and distributors specializing in agrochemicals.
• End-Product Connection:
  • Contributes to protecting staple food crops like rice from major pest damage, thus impacting food security in many regions. Compliance with MRLs on harvested produce is essential for trade.
• Supporting Services:
  • Agricultural extension services and crop advisors play a role in recommending its use as part of pest management strategies. Proper training on safe handling and application is important due to its toxicity.